Ambient temperature, rechargeable cells with metal salt-based electrodes and a system of cell component materials for use therein

ABSTRACT

A rechargeable battery or cell is disclosed in which the electrode active material consists of at least one nonmetallic compound or salt of the electropositive species on which the cell is based, and the electrolyte or electrolyte solvent consists predominantly of a halogen-bearing or chalcogen-bearing covalent compound such as SOCl 2  or SO 2 Cl 2 . Also disclosed are cell component materials which include electrodes that consist primarily of salts of the cell electropositive species and chemically compatible electrolytes. These latter electrolytes include several newly discovered ambient temperature molten salt systems based on the AlCl 3 —PCl 5  binary and the AlCl 3 —PCl 5 —PCl 3  ternaries.

A rechargeable battery or cell is disclosed in which the electrodeactive material consists of at least one nonmetallic compound or salt ofthe electropositive species on which the cell is based (e.g., Li⁺, Na⁺)and the electrolyte or electrolyte solvent consists predominantly of ahalogen- and/or chalcogen-bearing covalent compound such as SOCl₂ orSO₂Cl₂. Also disclosed are cell component materials which includeelectrodes that consist primarily of salts of the cell electropositivespecies and chemically-compatible electrolytes. These latterelectrolytes include several newly-discovered ambient temperature moltensalt systems based on the AlCl₃—PCl₅ binary and the AlCl₃—PCl₅—PCl₃ternaries.

BACKGROUND OF THE INVENTION

This invention relates to ambient temperature, rechargeable,non-aqueous, all-inorganic electrochemical cells. More specifically,this invention relates to such cells utilizing a new type of electrodein which the active material consists entirely of one or morenonmetallic compounds or salts of the electropositive species on whichthe cell is based (e.g., Li⁺, Na⁺), which is typically the same as thatof the main charge-carrying species in the electrolyte. In addition,this invention relates to ambient temperature, non-aqueous, inorganicelectrolytes for use in cells based on this new electrode type.

The ultimate goal of the research underlying the present invention is todevelop improved rechargeable batteries operating at or near roomtemperature that provide high specific energy and power densitiessuitable for electric vehicles. To allow for a wide range of ambientconditions, the desired temperature range for electric vehicle batteriesas envisioned in the long term by the U.S. Advanced Battery Consortium(USABC) is −40 to 85° C. At present, the lead-acid battery is theleading candidate for full-scale on-the-road electric vehicles due toits mature yet continually evolving technology and well-establishedmanufacturing base. Its chief limitation, however, is a low specificenergy which stems from a low cell voltage due to its use of aqueouselectrolytes and the relatively high cell component material molecularor formula weights. Thus, worldwide efforts have been in progress todevelop alternate battery chemistries that provide higher specificenergy and power densities as required to insure the long term economicviability of electric vehicles.

Lithium is among the most promising of rechargeable battery electrodeactive materials because of its high standard potential and lowelectrochemical equivalent weight. For many years, ambient temperaturerechargeable lithium batteries have been in an ongoing state of researchand development to provide lightweight, economical power sources for avariety of applications ranging from notebook computers and heartpacemakers to full-scale aerospace and transportation needs. A recentreview of all the different approaches taken to date in the design ofambient temperature rechargeable lithium batteries is provided byHossain (Chap. 36 in Handbook of Batteries, 2nd ed., ed. by D. Linden,McGraw-Hill, Inc., 1995).

From a review of the patent literature and other published studiespertaining to advanced batteries considered for use in electricvehicles, it appears that the majority of research in ambienttemperature lithium rechargeable batteries has been concentrated almostexclusively on two main types of cells which differ according to theform the lithium active material assumes during cell operation, i.e., i)those using lithium metal anodes, or ii) those using certain solidmaterials for both electrodes that can reversibly intercalate Li⁺cations. Both types of cells may utilize a variety of liquid or solid(e.g., polymer) electrolytes. In type (ii) cells, often referred to asLi-ion (“lion”) cells, Li⁺ cations are shuttled back and forth betweenthe electrodes during charging and discharging, and no free lithiummetal is present. Li-ion cells often utilize porous carbon at the anodeand lithiated first row transition metal oxides (e.g., Li_(x)MnO₂) atthe cathode, but many deviations from this basic design exist, e.g.,certain lithiated transition metal compounds with potentialssufficiently close to that of metallic lithium (e.g., Li_(x)WO₂) may beused as anodes, or porous carbon electrodes may be used at both thecathode and anode, each differing in the amount of surface area. Muchresearch has and continues to be devoted to the development of new(and/or to the improvement of existing) materials with enhanced Li⁺ ionintercalation storage capabilities. At present, however, neither lithiummetal anode nor Li-ion cells are sufficiently developed for large-scalecommercial use in electric vehicle batteries. For lithium metal anodebatteries, safety problems associated with metal dendrites abound, andfor Li-ion-type batteries, current limitations regarding long-termstorage and specific energy and power density need to be overcome.

The present invention, which makes use of all-metal salt electrodes, isa significant departure from conventional battery designs. A review ofthe prior art shows that there are relatively few designs using lithiumand other lightweight, electropositive metals in which the electrodeactive metal assumes the form of a distinct salt phase during some stageof cell operation. U.S. Pat. No. 4,154,902 by Schwartz describes bothprimary and rechargeable ambient temperature, non-aqueous cells inwhich, during the charging stage, the electrode active material is inthe form of a dithionite salt of an alkali or alkaline earth metal. Inthe cell design of Schwartz, the dithionite salt (e.g., Li₂S₂O₄) isdissolved in a suitable anhydrous solvent together with another salt ofthe same metal with a higher solubility (e.g., LiClO₄) to enhance theelectrolyte metal cation conductivity, and SO₂ is usually added atsaturation. During charging, the electrode active metal is deposited inmetallic form at the anode and SO₂ is produced at the cathode. Duringdischarging, the dithionite salt is reformed from metal cations producedat the anode by oxidation of the metal and S₂O₄ ²⁻ anions produced atthe cathode upon reduction of SO₂. Throughout cell operation, a steadysupply of dithionite salt is provided by the battery design whichemploys a system for forced circulation of the electrolyte.

It is well known that in primary lithium metal anode cells employing SO₂as the cathode active material, lithium dithionite salt, which has a lowsolubility in SO₂ as well as in most other electrolyte solvents, istypically formed during cell discharge and is deposited as anelectronically insulating layer (but with some ionic conductivity) onthe cathode current collector or substrate. Cell failure in such systemsoften occurs when the cathode current collector is entirely or almostentirely covered with solid Li₂S₂O₄. Under these conditions, furthercell operation is not possible, and cells in which the cathode currentcollector is coated with solid Li₂S₂O₄ are generally not considered tobe rechargeable.

Schwartz's invention is of interest in that it teaches that it ispossible to utilize the reaction product of spent anode active metal andcathode depolarizer (i.e., dithionite salt) as an electrode activematerial in rechargeable cells, at least in some systems. However,Schwartz's invention differs fundamentally from the present invention inthat the anode active metal is not always present in oxidized form butrather undergoes repeated oxidation and reduction during cell cycling(as in all metal anode cell designs). Also, the electrode active metaldithionite salt appears to be utilizable in Schwartz's cells only in theform of an electrolyte solute, and no dithionite (or other) salt phaseis deposited in solid form at either electrode at any stage of celloperation.

Another important aspect in which the present invention differs fromthat of Schwartz is that, in the latter invention, the rechargeableversion of Schwartz's cell is limited to only SO₂ since the cellchemistry is based on the use of dithionite salt as active material,whereas in the present invention, a wide variety of liquid cathodematerials can be utilized, and in combination with a wide variety ofelectrode solid phase compositions which are generally not restricted orfixed by the chemical composition of the liquid cathode employed. Asdiscussed in more detail below, it is far more difficult, both in theoryand in practice, to utilize an oxychloride as the cathode activematerial in rechargeable cells than it is to use SO₂. Hence, in thatconnection, it should be noted that it is only in the primary versionsof Schwartz's cell design (wherein temporary use is also made ofdithionite, but only as a precursor to the formation of lithium metalanodes in situ) that SOCl₂ and other oxychlorides can be used as cathodedepolarizers; such substances are not an integral part of any ofSchwartz's rechargeable cells.

U.S. Pat. No. 4,520,083 by Prater et al. describes an ambienttemperature, non-aqueous, rechargeable cell having a reactive metalanode of the second kind, i.e., one that forms an insoluble product upondischarge in combination with a suitable electrolyte. In the cell designdescribed therein, M⁺ cations (where M is the electrode active metal,e.g., Li) are expelled from the metal anode during discharging, and theyimmediately react with X⁻ anions which are present in the electrolyte ata concentration much greater than that of M⁺ cations to form aninsoluble metal salt, MX, which precipitates or deposits back on theanode. The electrolyte of this invention generally also contains acathode depolarizer such as SO₂. At the positive electrode, the cathodedepolarizer is reduced to a product which can be either soluble orinsoluble in the electrolyte. During charging, the slightly solubleactive metal salt on the anode (MX) redissolves, the X⁻ anions return tothe electrolyte solution, and the active metal cation M⁺ is reduced backto metal form at the anode. At the positive electrode, the reductionproduct is reoxidized back to the original cathode depolarizer. Asdiscussed by Prater et al., a low solubility in the electrolyte of bothM⁺ cations and MX salt is believed to be necessary for this type of cellto work as effectively as possible. This condition is met by preparingelectrolyte solutions which are at or near saturation in both M⁺ and MX.A large concentration of X⁻ relative to M⁺ is provided for by addinganother supporting salt, RX (wherein R is different from M), which issubstantially more soluble in the electrolyte than MX. To bring M⁺ tosaturation, a salt of M may be added to the electrolyte.

The cells of Prater et al. make use primarily of lithium (as well asother alkali and also alkaline earth metals) as the anode activematerial and multi-component electrolyte solvents consisting primarilyof inorganic or organic compounds consisting of Group IIIA, IVA, VA, andVI elements, e.g., nitriles, ethers, cyclic ethers, sulfur oxides, andsulfur oxyhalides. For the cathode depolarizer, a number of possibleredox couples were mentioned in the disclosure, e.g., Ag⁺/Ag, X₂/X⁻(where X is a halogen), Fe(CN)₆ ³⁻/Fe(CN)₆ ⁴⁻, and thianthrenecation/thianthrene, but the Examples employ only SO₂ as a cathodedepolarizer which was cited as being the most preferred.

The invention of Prater et al. differs fundamentally from the presentinvention in that the anode active metal species, M, undergoes repeatedoxidation and reduction during discharging and charging, as inconventional cells; hence, the anode active metal is not in the form ofa solid salt phase at both electrodes during any stage of celloperation. Also, the present invention and that of Prater et al. differin the type of predominant ionic charge carrier in the electrolyte; inthe latter invention, M⁺ cations are not transported back and forthbetween the electrodes. Finally, it appears that Prater's invention isrestricted to simple and demonstrably reversible redox couples such as,e.g., X_(n)/X^(m−) or X/X_(n) ^(m−) (where m and n are integers), incontrast to the present invention.

It is well known that not only sulfur dioxide (SO₂) but also thionylchloride (SOCl₂) and sulfuryl chloride (SO₂Cl₂), have long been used asliquid cathodes in lithium primary batteries designed for very highspecific energy and power density applications. In the development ofimproved electric vehicle batteries that can meet future energy andpower requirements, it would be highly desirable to be able to exploitthe promising properties of such cathode active materials in ambienttemperature, rechargeable cells. Of these three liquid cathodes, theoxychlorides, i.e., SOCl₂ and SO₂Cl₂, are more preferred since theyprovide the highest cell voltages, but up until now, their use has beenlimited almost exclusively to primary cells. Sulfur dioxide (SO₂) is theonly one of these liquid cathodes that has been utilized to anysignificant degree in lithium and other anode active metal rechargeablebatteries; this is most likely due to the much higher degree ofreversibility of its redox couple. Besides those designs describedabove, rechargeable cells using a lithium metal anode, a catholyte ofSO₂ containing a salt such as LiAlCl₄ added to impart a high Li⁺conductivity, and carbon as cathode current collector are also known,e.g., the system described in U.S. Pat. No. 4,513.067 by Kuo et al.

U.S. Pat. No. 5,260,148 by Idota describes and ambient temperaturerechargeable battery in which the anode active material consists of oneor more lithium compounds or salts, Li_(p)X, which are substantiallyinsoluble in the electrolyte based on organic solvent. Here, X is ananion which may be either singly atomic or polyatomic and p is the anionvalence of X. The electrolyte consists of an organic solvent containinga compound, A_(q)Y_(r), where A is a cation which may be either singlyatomic or polyatomic, and Y is an anion which may be either identicalwith or different from X provided that the lithium salt of Y issubstantially insoluble in the electrolyte. The cathode active materialconsists of an anion-doped compound or compound containing a cationwhich is the same as A of the compound A_(q)Y_(r) in the electrolyte. Inthe Examples provided, A is a polyatomic organic cation such astetrabutylammonium, tetraethylammonium, tetrapentylammonium,tetrabutylphosphonium, N-methylpyridinium, and N-methylpicolinium

When A is Li, there are two possibilities for an inorganic Li-containingcathode material according to Idota's disclosure, i.e., it may consistof a Li-doped transition metal chalcogenide such as Li_(x)Mn₂O₄ orLi_(x)CoO₂, or “a cathode material mixture may be prepared from thecathode active material by mixing it with the same ingredients as thoseused for preparing the anode material mixture.” For A=Li, however, thisimplies that the electrolyte conductivity cannot be made very high,since the main claim specifies that the lithium salt of Y must have alow solubility in the electrolyte. Specific examples of cells in which Ais Li were not provided, but in the disclosure, Idota states that forsuch cells, the electrolyte “is preferably based on a combination of thelithium compound and an inorganic lithium solid electrolyte. Further,lithium may be used therewith in such an amount that it dissolvesslightly.”

Idota's invention differs fundamentally from the present invention inseveral key aspects. Idota's invention for anode active material isrestricted to organic solvent electrolytes. As will be shown, thepresent invention provides a wide variety of recipes for the electrodesalt mixtures, far more than envisioned by Idota. Whereas Idota'sinvention is restricted to the use of Li as the anode active metalspecies, the present invention has been demonstrated on a wide varietyof anode active metal species. Also, various additives such as, e.g.,aliovalent salts that give rise to substantially improved electrodeproperties were discovered and developed, and are disclosed herein. Theoptimization of multi-component all-metal salt electrode compositionsfor A=Li is not considered in Idota's invention.

The present invention also makes advantageous use of certain liquidcathode materials which participate in a key way in the electrode halfcell reactions, whereas Idota's invention is restricted to organicsolvent electrolytes. These liquid cathodes include those for which thehalf cell reactions are highly irreversible, i.e., the sulfuroxychlorides SOCl₂ and SO₂Cl₂, and hence not amenable to conventionalrechargeable cell designs. Such liquid cathodes would also be utilizablein Idota's invention for A=Li with either of the two possible types ofinorganic cathode materials mentioned above, but that possibility wasnot mentioned in Idota's disclosure.

The present invention also addresses the problem ofelectrode-electrolyte compatibility, whereby for a given electrodematerial, suitable electrolytes are used so that high exchange currentdensities at the electrode-electrolyte interface can be realized. Theexchange current density provides a measure of how quickly thedetermining half-cell reactions can take place, and thus, high exchangecurrents are well known to be necessary for achieving high currentcarrying capabilites and high power capacities in electrochemical cells.The present invention utilizes a variety of inorganic electrolytes whichgive rise to highly promising cell properties believed to arise fromhigh exchange current densities. As will be shown, these electrolytesinclude not only the sulfur oxychlorides, for which such high exchangecurrents have previously been manifested by the high performancecapabilities of Li primary batteries, but also certain newly-discoveredambient temperature molten salt electrolytes disclosed herein. Thus,another key aspect of the present invention is the discovery anddevelopment of compatible electrolytes for the metal salt electrodessuitable for larger size, high energy and power density rechargeablecells, a problem which Idota's invention does not address.

In contrast to SO₂, the oxyhalide solvents, particularly SOCl₂, haverarely been used in rechargeable batteries. This is because theirpractical use in such systems has generally been precluded by the highdegree of irreversibility of the electroreduction reaction, which makesthe in situ regeneration of any spent liquid cathode solventimpracticable. For primary lithium metal anode-SOCl₂ cathode cells, theoverall electroreduction reaction is

4Li+2SOCl₂→4LiCl+S+SO₂  (1)

where the LiCl is deposited at the positive electrode current collector(typically porous carbon). A prerequisite for the use of either SO₂Cl₂or SOCl₂ as a liquid cathode in any rechargeable cell is that somemechanism be provided for the facile regeneration of spent cathode fromthe electroreduction products. For SOCl₂, a mechanism would have to beprovided for the recombination and re-reaction of three distinctchemical species, i.e., S, SO₂, and Cl₂. For SO₂Cl₂, the onlyelectroreduction products are SO₂ and Cl₂, and hence, the reformation ofSO₂Cl₂ is a more straightforward process than that of SOCl₂ because onlytwo species are involved. Also, the SO₂Cl₂ reformation reaction is knownto be catalyzable by carbon.

Even for SO₂Cl₂, however, very few studies have been published on theuse of such liquid cathodes in rechargeable cells. In one study by bySmith et al. (J. Electrochem. Soc., 137, 602 [1990]), therechargeability of the Li—SO₂Cl₂ couple was demonstrated at roomtemperature on small prototype cells with lithium metal anodes andcarbon cathodes and test cells with all-lithium reference, test, andcounter electrodes using 1.5 M LiAlCl₄—SO₂Cl₂ as the catholyte. Bothtypes of cells were found to exhibit moderately good rechargeability andefficiency, but in all cases, the number of cycles was generally limitedto well below 60 due to cell failure. As discussed by Smith et al. andshown by the data, there appear to be two main causes of failure inLi—SO₂Cl₂ cells, i.e., lithium metal dendrite formation, and a slow rateof regeneration of spent SO₂Cl₂ from Cl₂ and SO₂. The latter phenomenonmay occur in conjunction with certain deleterious side reactions such asCl₂ attack of Li, resulting in a gradual depletion of SO₂Cl₂ from thecell. Whichever mode of failure predominates appears to be dependent ona number of interrelated factors, including the prior state of cellcharge, the inter-electrode separation distance, and whether the cell isanode- or cathode-limited.

In the Smith et al. study, the effects of changes in catholytecomposition were studied for the small prototype cells. Increasing theLiAlCl₄ concentration from 1.5 to 3.0 M was found to double the cathodecycle life, which was attributed to a faster dissolution of lithiumdendrites in the more corrosive 3.0 M electrolyte. Adding SO₂ was foundto have no effect on the cathode efficiency, but the discharge voltageregulation was greatly improved. This improvement was attributed to thesuppression of SO₂Cl₂ dissociation by SO₂ which eliminates dissolved Cl₂from the catholyte, thus restricting the cathode reduction reaction toSO₂Cl₂ alone rather than a mixture of Cl₂ and SO₂Cl₂. Adding Cl₂ and/orSOCl₂ to this system failed to regulate the discharge voltage anddegraded cathode cycling efficiency to half the baseline electrolytevalue. This undesirable effect might be due to the type of anodes usedin the cells of the Smith et al. study, i.e., metallic lithium, whichmay act more as chlorine scavengers rather than as promoters of the insitu regeneration of the SO₂Cl₂ cathode.

U.S. Pat. No. 4,894,298 by Vukson et al. describes a high temperaturealkali metal plus halide rechargeable cell with SO₂Cl₂ catholyte. Themost typical version of this cell consists of a negative electrode ofsodium metal and a positive electrode which includes a solid NaCl andSO₂Cl₂ catholyte to which NaAlCl₄ and AlCl₃ are usually added to imparta high Na⁺ ionic conductivity. During charging, Na⁺ cations are releasedfrom the NaCl at the positive electrode and are reduced at the negativeelectrode to metallic form. Also, a volatile reaction product isproduced which is believed to consist mostly of Cl₂ gas formed at thepositive electrode by anodic oxidation of the Cl⁻ anions from the NaCl.During discharging, the sodium metal at the negative electrode isoxidized to Na⁺ cations which migrate to the positive electrode whereinSO₂Cl₂ is reduced to Cl⁻ anions and SO₂, the latter of which is believedto constitute most of the volatile reaction product that is a part ofthe discharging reaction. The Cl⁻ anions combine with Na⁺ cations toreform NaCl at the positive electrode.

As Vukson et al. also teach, the ability to regenerate spent SO₂Cl₂catholyte in situ is essential to the rechargeability of any cellincorporating such material. Vukson et al. provide a physical means inthe cell design whereby gaseous SO₂ and Cl₂ generated at the positiveelectrode during charging and discharging, respectively, can be storedand later recombined as necessary to regenerate the SO₂Cl₂ catholyte. Inthat way, rechargeability of a cell utilizing SO₂Cl₂ as a catholyte ismade possible even though the types of electrode active materialsemployed in designs of the type utilized by Vukson et al. make itinfeasible to generate SO₂ and Cl₂ simultaneously during cell operation.The invention of Vukson et al. is illustrative of the types of elaboratemeans that sometimes have to be employed to make it feasible for SO₂ andCl₂ to recombine to reform SO₂Cl₂.

As will be shown, an important aspect of the present invention is thatit is now possible to utilize fully such high performance liquidcathodes as SOCl₂ and SO₂Cl₂ in ambient temperature rechargeablebatteries. This aspect stems from the discovery that certain all-metalsalt electrode compositions were found to work quite well with bothSOCl₂ and SO₂Cl₂. Possible theories and chemical mechanisms underlyingthis discovery are given below (see “Summary of Invention”). The presentinvention is the first known wherein cathode redox couples more complexthat those of type X_(n)/X^(m−) or X/X_(n) ^(m−) can be utilized inrechargeable cells.

Besides those electrolytes based on SOCl₂ and SO₂Cl₂, the author alsodiscovered several new families of ambient temperature, all-inorganicmolten salt electrolytes that work well with many of the all-metal saltelectrode compositions which are disclosed herein. These molten saltsare based on the low-melting binary, AlCl₃—PCl₅, to which either PCl₃,POCl₃, or PSCl₃ may be added. The synergistic effects of combiningall-metal salt electrodes with these electrolytes are believed to stemfrom higher exchange current densities at the electrode-electrolyteinterface. Also, depending on the metal salts comprising the electrodesolid phases, these molten salt electrolytes may also serves as liquidelectrodes (usually cathodes) since they all contain components that mayundergo a variety of redox reactions involving either the uptake orliberation of Cl⁻ ions from the phosphorus-containing components (i.e.,PCl₅, PCl₃, POCl₃, and/or PSCl₃). Such redox reactions are alsoconsiderably more complex than those of type X_(n)/X^(m−) or X/X_(n)^(m−).

It is the principle object of the present invention to provide analternative approach to the development of high specific energy andpower density rechargeable batteries that are potentially suitable forelectric vehicle applications. This objective is accomplished by the useof a new electrode design together with supporting all-inorganic cellcomponent materials, and a demonstration of the viability of saidelectrode design and cell component materials in larger-size prototypecells.

It is a further object to provide a wide range of rechargeable cellcomponent materials for the construction of batteries based on the newelectrode design. These materials include not only new electrodecompositions utilizing metal salts as the principle electrode activematerial, but also new ambient temperature molten salt electrolytes thatpossess all the desired materials properties and appear to worksynergistically with most of the electrode compositions developedherein.

It is a further object to provide means, utilizing the new electrodedesign described herein, for the use of promising and complex liquid orsoluble electrodes in a rechargeable cell. In particular, it is afurther object to provide means for the exploitation of both SOCl₂ andSO₂Cl₂ as liquid cathodes for high specific energy and power densitycells. This is accomplished by the development of compatible all-metalsalt electrodes of suitable chemical composition, as well as thediscovery of an electrochemical “pre-treatment” of the catholyte thatfurther improves the cell performance.

It is a further object to provide fabrication procedures for theconstruction of larger-size cell prototypes that effectively utilize themost promising cell materials discovered to date.

Other objects and advantages of the invention will become apparent fromthe following description and examples thereof.

SUMMARY OF INVENTION

The present invention consists of a new type of rechargeable cell inwhich the electrode active material is in the form of a metal saltthroughout all stages of cell operation. In the all-metal saltelectrodes described herein, the active electrode material consistsentirely of one or more metal salts wherein typically, the metal is thesame as that of the main charge-carrying species in the electrolyte(e.g., Li⁺). In cells based on the new design, the positive and negativeelectrodes each consist of a metal salt or salt mixture with or withoutother additives that enhance the cell performance. The physicochemicalprocesses that occur at the electrodes during charging and dischargingmay be described (e.g., for the negative electrode) as an electrolysisor dissociation of the electrode active metal salt to its cations andanions during discharging, and a redeposition or “plating out” of thesolid metal salt layer during charging. (A reversal of these processesoccurs at the positive electrode.)

To achieve a high cycling number, the electrodes should consistprimarily of one or more salts which are substantially insoluble in theelectrolyte. In practice, however, it was found that in general, smallamounts of salts which are more soluble improve the overall performanceof the cell and thus, they are also a preferred minor constituent of theelectrode salt mixture. Preferably, all electrode active metal saltsshould have as low a molecular weight as possible to achieve the highestpossible specific energy density.

In this invention, the electrodes are supported as coatings or films ona suitable substrate or support material. The substrate materials arechosen such that they may somehow promote the half-cell reactionsinvolving the metal salt anions described below that are believed to beinvolved in the power generation of the cell. A number of electrode andsubstrate compositions, all suitable for use at ambient temperature andmany optimized for high energy and power density applications with extraadditives (e.g., metal oxides or halides wherein the metal differs fromthat of the main cation charge carrier) have been developed and aredescribed herein.

To realize the full potential of this invention, these all-metal saltelectrodes should be used with chemically-compatible electrolytes toachieve the highest possible specific power density and cycle number. By“chemically-compatible” it is meant that while the electrode issubstantially insoluble in the electrolyte, the exchange current densityis made as high as possible by suitable adjustments in the electrolyte(or catholyte) chemical composition. Although the mechanism(s) by whichthe latter process may be realized in practice are not well understoodfor cells employing the new electrode design, one possibility is thatcertain additives or components of the electrolytes disclosed herein mayplay the role of a catalyst for the electrolysis or dissociation of themetal salt electrode, e.g., as believed to occur during discharging atthe negative electrode. Such chemically-compatible electrolytes are alsoa key aspect of this invention.

The electrode design of the present invention makes possible, for thefirst time, the effective utilization of oxychloride liquid cathodes inambient temperature, rechargeable cells. The oxychlorides that have beendemonstrated to be useable in this invention include thionyl chloride(SOCl₂) which, as far as the author is aware, has never been utilized asa cathode active material in any rechargeable cell of any kind. Theutilization of such oxyhalides as cathodes (usually in the form ofcatholytes) is made possible by the discovery of a family of suitablechemical compositions for the salt mixtures that constitute the solidportions of the electrodes. As explained in more detail below, the factthat SO₂Cl₂ and especially SOCl₂ can now be used in rechargeable cellsbased on the new electrode design is attributed to the simultaneousgeneration of SO₂ and Cl₂, produced at the cathode and anode,respectively, during both charging and discharging, which in turnresults from the introduction of extra nonmetallic electrode activematerial (i.e., chlorine) to the system

Also disclosed herein are new all-inorganic, ionic complex liquidelectrolytes which are based on the ambient temperature molten saltternaries, AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃.These new electrolytes lend themselves very well to practicalapplications because of their high ionic conductivities, low vaporpressures, wide liquid temperature ranges, and good chemicalcompatibilities with a variety of electrode salts. In addition, they mayparticipate in a variety of redox reactions which may also enable themto act as a liquid electrode, depending on the chemical compositions ofthe electrode solid phases present.

In cells utilizing all-metal salt electrodes, the electrodephysicochemical processes that occur during charging and discharging asoutline above are consistent with the phenomenon of metal cations of theelectrode active metal salts being transported or “shuttled” back andforth between electrodes during cell operation while maintainingsubstantially the same positive charge throughout. This is because bothelectrodes start out in metal salt form and thus, metal salt anionicspecies are always available at each electrode site to “meet up with”and reform the metal salt during charging and discharging. That such atransport process for the electrode active metal species occurs in cellsof the present design is manifested by the absence or near-absence ofmetal layers during the electrode plating out process.

Whereas the metal cations are shuttled back and forth between electrodesand do not participate in any redox reactions, the metal salt anions arebelieved to partake in a variety of half-cell reactions that essentiallydetermine the cell voltage and also enable them to act as “hosts” forthe metal cations at each electrode. Although not completely understoodfor each cell chemistry type described herein, these half-cell reactionsor processes are believed to fall into one of three categories. Duringanodic oxidation, these reactions are believed to occur as follows: i)the anion may intercalate into some host material that is a part of theelectrode substrate (e.g., carbon), the redox equilibria involving onlythe donation of an electron from the host material valence band to theexternal circuit; ii) the anion may react with some chemical component(e.g., a metal or a transition metal compound) in the electrode orsubstrate thereof to form an insoluble compound, the redox equilibriainvolving both a chemical reaction and electron transfer to theelectrode current collector and iii) the anion may reform, by anodicoxidation, a chemical species that is a necessary reactant for the insitu reformation or regeneration of a spent liquid cathode from some ofits electroreduction products wherein again, an electron is donated ortransferred to the electrode current collector. During cathodicreduction, half-cell reactions (i)-(iii) are reversed.

It should be noted that is possible for two or more half-cell reactiontypes as outlined above to occur in the same cell; each reaction willoccur to a degree that depends on the particular cell chemistry andstate of charge. Also, since metal cations do not undergo reduction,they may either recombine with anions to form or reform a solid metalsalt phase, and/or they may intercalate or otherwise somehow beincorporated in one or more solid phases in the electrode, e.g., carbon,a first row transition metal oxide (e.g., MnO₂), or some electrodeactive metal salt. It is all these phenomena, which are additive, thatare, when taken in combination, believed to be the origin of the highpractical cathode capacities attainable using electrodes of this type.

The following cases (i)-(iii), describe by illustration the threedifferent types of electrode processes involving metal salt anions thatare believed to occur in the cells described herein. Simplified, and insome cases somewhat idealized, hypothetical cells based on the newelectrode design, but with chemical components that are typical of theExamples disclosed herein, are used as the models for these cases. Thenumbering of these three cases (i.e., [i]-[iii]) corresponds to theorder of the numbering of the three processes as given above. While eachcase is focused mainly on one electrode process, it should be noted thatsince these cells are generally complex, multi-component systems, it ishighly likely that more than one type of process may occur, as discussedbelow.

(i): Intercalation

In this cell, the electrodes each consist of LiCl—CaCl₂ mixtures (withCaCl₂ present, e.g., at a concentration of 20 ml %) coated on carbon.The electrolyte may be either solvent- or molten salt-based. TheLiCl—CaCl₂ mixtures are processed such that they form solid solutionswherein the Ca is believed to be incorporated substitutionally onlithium sites in the LiCl crystal structure, with the formation ofcompensating lithium vacancy point defects.

During discharge, the Cl⁻ anions released at the LiCl—CaCl₂ negativeelectrode either may be incorporated into the LiCl—CaCl₂ coating or,more probably, may intercalate into the carbon support, while Li⁺cations are expelled into the electrolyte and migrate towards thepositive electrode. In the latter case, one electron per Cl⁻ anion thatundergoes this process is released from the carbon valence band to theexternal circuit. (Alternatively, the electron released to the externalcircuit may come from the Cl⁻ anion, the latter forming a neutral Clatom which then acts as an electron acceptor for carbon.)

At the positive electrode, there are three possibilities for incomingLi⁺ cations, i.e., i) they may be incorporated into the LiCl—CaCl₂coating, ii) they may be intercalated into the carbon substrate, or iii)they may combine with intercalated Cl which is already present at thepositive electrode from a previous cell charging to form (or reform)LiCl. For possibility (i), it is believed that Li⁺ cations may beincorporated within the LiCl—CaCl₂ coating on the lithium vacanciesformed originally upon introduction of Ca into the LiCl crystalstructure. In the process, one point defect annihilates the other on thelithium sublattice in crystalline LiCl, and to preserveelectroneutrality, some species within the positive electrode mustundergo reduction (i.e., by accepting an electron from the externalcircuit). For possibility (ii), this process is well known from theliterature on battery intercalation materials to be accompanied by theacceptance of one electron per Li⁺ cation from the external circuit bythe carbon host material conduction band. If possibility (iii) occurs,then the most likely species for reduction is the neutral intercalatedCl atoms which become negatively ionized and then combine with Li⁺cations to form (or reform) electrically neutral LiCl.

(ii): Solid Phase Formation at an Electrode

In this cell, the electrodes each consist of a metal halide or metalhalide mixture coated on a support containing nickel or copper. Formetal chloride-based electrodes, the Cl⁻ anions formed, e.g., at thenegative electrode during cell discharge, may react with the metal inthe electrode substrate or support to form the corresponding metalchloride, i.e., CuCl₂ and NiCl₂, for copper and nickel metal supports,respectively. In the process, one electron per Cl⁻ anion that undergoessaid chemical reaction is released to the external circuit.

In another cell that operates on the same principle, the electrodesconsist of mixtures of one or more metal halides and a transition metalcompound such as CuCl, FeCl₂, CoO₂, or MnO₂ coated on a carbon orcarbon-on-metal substrate. For metal chloride-containing electrodes, theCl⁻ anions formed upon discharge at the negative electrode may reactwith the transition metal compound to form a compound of higher metaloxidation state. For example, Cl⁻ may react with CuCl or FeCl₂ to form,respectively, CuCl₂ or FeCl₃, with an attendant release of electrons tothe external circuit (i.e., one per Cl⁻ anion involved).

(iii): Liquid Cathode Regeneration

A. Thionyl Chloride (SOCl₂)

In this cell, the positive and negative electrodes each consist of aLiCl or LiCl-containing salt mixture coated on carbon, and the catholyteconsists of LiAlCl₄ (which is present, e.g., at a concentration of 1.5M) dissolved in SOCl₂.

The ability of the SOCl₂-based cells described herein to be rechargedwhen metal salt electrodes of a suitable chemical composition are usedis one manifestation of the novelty of the new cell design describedherein which makes possible certain half-cell reactions that help toregenerate the SOCl₂ solvent that are not possible in other celldesigns. During charging, Cl₂ gas is formed by the oxidation of Cl⁻anions which are, in turn, formed upon dissociation or electrolysis ofLiCl. The latter process is catalyzed by a Lewis acid such as AlCl₃which is typically added to SOCl₂ to increase the Li⁺ solubility. Sincethe solubility of Cl₂ in SOCl₂ is relatively low, most of the Cl₂ gas isbelieved to be adsorbed on the carbon supports. During SOCl₂electroreduction, SO₂, S, and Cl⁻ anions are formed, and in conventionalLi battery designs, this process is normally irreversible, as discussedabove and shown in reaction (1). In the new electrode design disclosedherein, however, the rechargeability of SOCl₂-based cells is madefeasible by the ability of spent SOCl₂ to be regenerated. The latterprocess, in turn, is made possible by the formation of Cl⁻ anions duringLiCl dissociation or electrolysis and concomitant formation of Cl₂ gas,the latter of which is believed to react with S and SO₂ in solution toform SCl₂ and SO₂Cl₂ which are reaction intermediates for SOCl₂.

In its simplest configuration, the SOCl₂-based rechargeable cell is anall-chloride system consisting of pure LiCl electrodes and SOCl₂—LiAlCl₄catholyte. During discharging, the half cell reactions that are believedto occur at the electrodes are as follows:

Negative Electrode: 4LiCl − 4e⁻ → 4Li⁺¹ + 4Cl⁻ − 4e⁻ → 4Li⁺¹ + 2Cl₂Positive Electrode: 2SOCl₂ + 4e⁻ → S + SO₂ + 4Cl⁻ Overall: 4LiCl +2SOCl₂ → S + SO₂ + 2Cl₂ + 4Cl⁻ + 4Li⁺¹ → S + SO₂ + 2Cl₂ + 4LiCl(positive electrode)

The newly-formed LiCl at the positive electrode is made from Li⁺¹cations generated by dissociation or electrolysis of LiCl at thenegative electrode which combine with Cl⁻ anions produced byelectroreduction of SOCl₂ at the positive electrode substrate. From theabove reactions, it can readily be seen that one mole of LiCl isdeposited at the positive electrode for every mole of LiCl that iselectrolyzed at the negative electrode during discharging.

As shown above on the right hand side of the overall cell reaction, S,SO₂, and anodically-produced Cl₂ are produced during discharging. Inorder to achieve a steady state catholyte composition duringdischarging, one that is also suitable for reuse in rechargeablebatteries, it is necessary for the reformation reaction for SOCl₂ tooccur at a rate comparable to that of the SOCl₂ electroreductionreaction. The simplest possible, and also most likely, reaction schemefor the in situ reformation of SOCl₂ is the oxidation of SCl₂ by SO₂Cl₂,i.e.,

SO₂Cl₂+SCl₂→2SOCl₂  (2)

where the SO₂Cl₂ and SCl₂ reaction intermediates are believed to beproduced from S, SO₂ and Cl₂ according to

SO₂+Cl₂→SO₂Cl₂  (3)

S+Cl₂→SCl₂  (4)

Reaction (2), which is known to be catalyzable by charcoal, has longbeen used in the industrial preparation of SOCl₂. Also, this reactionappears to be quite kinetically uncomplicated; all that would berequired is for one of the oxygen atoms on the (slightly distorted)S-centered SO₂Cl₂ tetrahedron to first bond with the S atom on a nearbySCl₂ molecule then break away from the S atom on the SO₂Cl₂ molecule.Note that reaction (2) is not important in conventional Li—SOCl₂ primarybatteries because, in these systems, the free Cl₂ content in thecatholyte is not continuously replenished by anodic oxidation of anyCl⁻-bearing species and thus, SO₂Cl₂ and SCl₂ are not formed insufficient concentrations from the SOCl₂ electroreduction byproducts.This may explain, at least in part, why SOCl₂-based cells such as theone described herein are rechargeable, whereas conventional SOCl₂-basedcells wherein SOCl₂ is the cathode active material are generally not.

In the above discussion, it is assumed that the cell current density issufficiently low such that any Cl₂ that is produced by anodic oxidationmay be consumed quickly enough in the SOCl₂ regeneration reactions sothat there is no Cl₂ pressure buildup. In practice, such problems mayoccur in certain cells, because the solubility of Cl₂ in SOCl₂ (and alsoSO₂Cl₂) catholytes is low, and it is also well below that of SO₂.

B. Sulfuryl Chloride (SO₂Cl₂)

In this cell, the positive and negative electrodes each consist of aLiCl or LiCl-containing salt mixture coated on carbon, and the catholyteconsists of LiAlCl₄ (which is present, e.g., at a concentration of 1.5M) dissolved in SO₂Cl₂.

In conventional Li metal/SO₂Cl₂ primary batteries, the overall celldischarge reaction is

2Li+SO₂Cl₂→2Li⁺¹+2Cl⁻+SO₂→2LiCl+SO₂  (5)

where the LiCl formed is deposited at the positive electrode substrate.The rechargeable SO₂Cl₂ cells described herein differ fundamentally fromconventional designs in that the starting negative electrode material isa salt; in the simplest cell configuration, each electrode consists ofLiCl supported on a substrate such as carbon. Since the Li in LiCl isalready in the +1 state, no further oxidation of Li at the anode ispossible. During discharging, however, some other chemical species atthe negative electrode must undergo oxidation while SO₂Cl₂ is beingreduced in order to preserve the overall charge neutrality in the celland complete the electrical circuit. In this cell, the most likelycandidate species for oxidation is the Cl⁻ in LiCl.

Thus, for rechargeable LiCl/SO₂Cl₂ cells based on the new design, thefollowing reactions are believed to take place during discharging:

Negative Electrode: 2LiCl − 2e⁻ → 2Li⁺¹ + 2Cl⁻ − 2e⁻ → 2Li⁺¹ + Cl₂Positive Electrode: SOCl₂ + 2e⁻ → SO₂ + 2Cl⁻ Overall: 2LiCl + SO₂Cl₂ →SO₂ + 2Cl₂ + 2Li⁺¹ + Cl₂ → SO₂ + Cl₂ + 2LiCl (positive electrode)

The mode of regeneration of the SO₂Cl₂ catholyte in these cells isexpected to be simpler than that believed to take place in SOCl₂-basedcells, i.e., the SO₂ and Cl₂ formed upon discharging can reform SO₂Cl₂in one step according to

SO₂+Cl₂→SO₂Cl₂  (6)

Reaction (6), which is thermodynamically favored at room temperature, isalso known to be catalyzable by charcoal.

C. AlCl₃—PCl₅—PCl₃

In the ternary systems, AlCl₃—PCl₅—R, where R=PCl₃, POCl₃, or PSCl₃, thephosphorus-containing components may all play the role of an electrodeactive component because the valence of P may assume either +3 or +5,depending on the chemical environment. The simplest redox reactionsinvolving phosphorus in these ternaries are believed to occur in theAlCl₃—PCl₅—PCl₃ system, wherein Cl₂, PCl_(x) groups and Cl⁻ anions arethe only chemical species involved.

In this cell, the electrolyte consists of an equimolar mixture of AlCl₃and PCl₅ with PCl₃ present at its saturation concentration such thatAlCl₃, PCl₅, and PCl₃ are present at about a 10:10:3 molar ratio. Theelectrode active material solid phase consists of a metal chloride suchas LiCl or NaCl. During discharging, two half cell reactions arepossible at the negative electrode, i.e.,

2Cl⁻−2e ⁻→Cl₂  (7)

PCl₃+2Cl⁻−2e ⁻→PCl₅  (8)

At the positive electrode, dissolved Cl₂ generated at the negativeelectrode may undergo reduction according to

Cl₂+2e ⁻→2Cl⁻  (9)

However, given the expected low solubility of Cl₂ in AlCl₃—PCl₅—PCl₃mixtures, as well as the expected PCl₅ regeneration reaction, i.e.,

Cl₂+PCl₃→PCl₅  (10)

the more likely predominant reaction is the reduction of PCl₅ to Cl⁻ andPCl₃ i.e.,

PCl₅+2e ⁻→PCl₃+2Cl⁻  (11)

where the Cl⁻ anions combine with metal cations to plate out metal saltat the positive electrode and PCl₃ stays in the electrolyte solution.Thus, in cells utilizing AlCl₃—PCl₅—PCl₃ mixtures, PCl₃ and PCl₅ may,respectively, act as liquid anode and cathode components, respectively,depending on the state of cell charge. During cell operation, thePCl₅:PCl₃ ratio may undergo momentary fluctuations if any of the abovereactions are kinetically limiting.

Assuming reactions (7) and (11) are predominant, i.e., by analogy withSOCl₂ and SO₂Cl₂ discussed above, the overall cell reaction is

PCl₅+2Cl⁻→PCl₃+Cl₂+2Cl⁻  (12)

wherein during this process, one mole of M⁺ cations is expelled into theelectrolyte and one mole of MCl is plated out at the positive electrodefor every mole of MCl dissociated at the negative electrode. If reaction(10) takes place sufficiently quickly, then the PCl₅:PCl₃ ratio staysconstant and there is no buildup of PCl₃ or Cl₂ during discharging.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the ionic conductivity vs. reciprocal temperature from −20°C. to 120° C. of 2AlCl₃—PCl₅ with LiCl additions of 0, 10, and 20 m %.

FIG. 2 is a plot of the charging-discharging curve for Cell A of Example#4.

FIG. 3a shows the cell voltage and current versus time duringdischarging for Cell B of Example #4. FIG. 3b shows the cell outputpower versus time during discharging for the same cell.

FIG. 4a shows the cell voltage and current versus time duringdischarging for Cell E of Example #4. FIG. 4b shows the cell outputpower versus time during discharging for the same cell.

FIG. 5a is a plot of the charging-discharging curve during the fourthcycle for Cell G of Example #4. FIG. 5b is a plot of the mid-cyclecharging-discharging curve for the same cell.

FIG. 6 is a plot of the charging-discharging curve for Cell H of Example#4.

FIG. 7a shows the cell voltage versus time during discharging for forCell A of Example #6. FIG. 7b shows the cell output power versus timeduring discharging for the same cell.

FIGS. 8a and b show the cell voltage versus time during discharging fordischarging currents of 5 mA and 2 mA, respectively, for Cell B ofExample #6. FIG. 8c shows the cell voltage versus time duringdischarging for Cell C of Example #6.

FIGS. 9a and b show the cell voltage versus time during dischargingduring the second and third cycles for Cell D of Example #6.

FIG. 10 shows the cell voltage versus time during discharging for Cell Aof Example #8.

FIG. 11a shows the cell voltage versus time during discharging for CellB of Example #8. FIG. 11b shows the cell output power versus time duringdischarging for the same cell.

FIGS. 12a-c show the cell voltage versus time during discharging for thefirst, 50th, and 100th cycles for Cell C of Example #8.

FIG. 13 is a plot of the charging-discharging curve for Cell A ofExample #26.

FIG. 14a shows the cell voltage and current versus time duringdischarging for Cell C of Example #26. FIG. 14b shows the cell outputpower versus time during discharging for the same cell.

FIG. 15 shows the cell voltage versus time during discharging for Cell Bof Example #27.

FIG. 16 shows the cell voltage versus time during discharging for Cell Bof Example #28.

DETAILED DESCRIPTION OF THE INVENTION

In the all-metal salt electrodes, the electrode active material consistsentirely of one or more metal salts. Typically, the anode active metalis the same as that of the main charge-carrying species in theelectrolyte, but cells of this invention may utilize a variety ofelectrolytes, including those in which metal cations of the main anodeactive metal are not present. Although metal salt electrode activematerials are the main focus of the present work, it should be notedthat the new cell concept introduced herein is not necessarilyrestricted to electrodes based solely on metal cations. Any compoundthat, upon dissociation, is capable of forming anion-cation pairs,including those in which the cation is nonmetallic (e.g., NH₄ ⁺, B³⁺),may be used to construct a cell based on the principles described hereinby suitable combinations of cell component materials without departingfrom the spirit and scope of this invention. All-metal salt electrodesin which the electrode active metal is a Group IA, IIA or IIIA elementhave been demonstrated herein to work quite well in ambient temperature,rechargeable cells as shown in the Examples below, but to achieve thehighest possible specific energy densities, the lightest and mostelectropositive metals, e.g., Li, are generally most preferred.

In the context of this disclosure, the term “metal salt” is used as ashorthand expression to refer to any compound that, upon dissociation,is capable of yielding metal cations and single atomic or complexanions. The metal compounds that have been found to be the most usefulfor the present application are those that are inorganic, largely ionicsubstances which are true salts in the conventional sense, e.g., themetal halides, pseudohalides, and certain oxyanion compounds. The term“pseudohalide” refers to any monovalent, polyatomic anion with chemicaland electronic properties very similar to those of the halides, e.g.,CN⁻, SCN⁻, OCN⁻, and SeCN⁻. Examples of pseudohalide salts are thealkali metal cyanides (MCN), thiocyanates (MSCN), and cyanates (MOCN),where M is an alkali metal, and the alkaline earth metal cyanides(M′(CN)₂), thiocyanates (M′(SCN)₂), and cyanates (M′(OCN)₂), where M′ isan alkaline earth metal. The term “oxyanion” refers to any anion complexwith oxygen anions as ligands. Examples of oxyanion salts are the alkalimetal sulfates (M₂SO₄), nitrates (MNO₃), perchlorates (MClO₄), andphosphates (M₃PO₄), where M is an alkali metal, and the alkaline earthmetal sulfates (M′SO₄), nitrates (M′(NO₃)₂), perchlorates (M′(ClO₄)₂),and phosphates (M′₃(PO₄)₂), where M′ is an alkali metal. The term “metalsalt” as used herein may also include other inorganic substances notcommonly referred to as salts such as the metal oxides, e.g., Li₂O, andmetal sulfides, e.g., Na₂S. As the principle electrically-activeelectrode chemical species, many of these latter compounds have alsobeen shown to result in promising cell properties.

In the design of all-metal salt electrodes for high specific energy andpower density batteries, one important consideration is that thetheoretical charge storage or current capacities of each metal salt inthe electrode be as high as possible. For the lighter metal elementssuch as Li, Na, Ca, and Mg, the theoretical storage capacities of manyof their salts well exceed those of most other cathode and anodematerials currently in use with the exception of metallic lithium (e.g.,the theoretical storage capacity of Li₂O is 1794 Ah/kg). Other examplesof high capacity metal salts are Li₂S, LiF, LiCl, Li₂CO₃, and CaCl₂.Generally, metal salts with larger anion atomic or molecular weights(e.g., those containing the heavier halogens or chalcogens) are lesspreferred, all other considerations being more or less equal.

The cell capacity that can be attained in practical cells is determinedby the number of metal salt cations that can be transferred from thepositive to the negative electrode during charging (i.e., the cathodecapacity). That quantity, in turn, is believed to be determined by thedegree to which the metal salt anions can participate in one or morecell reactions as outlined above that will enable them to be intemporary storage until they are able to recombine with the metalcations to reform the metal salt electrode, e.g., at the positiveelectrode during discharging. The degree to which an anion canparticipate in any given half-cell reaction is governed not only bythermodynamic but also by kinetic considerations.

Two main types of metal salts may be utilized in the present invention,i.e., those that are substantially insoluble in the electrolyte, andthose that are somewhat soluble. To achieve a high cycling number, ithas been found that in general, the electrodes should consist mainly ofinsoluble salts (e.g., metal oxides, carbonates, sulfates). Too high asalt solubility presents problems, because for every ion pair that isdissolved in the electrolyte, that is one less metal cation availablefor the storage of electrical energy in the cell (or alternatively, oneless anion that can act as host for the arrival of some metal cation insome future cycle). In practice, however, minor amounts (˜10-20 m %) ofthe more soluble salts (e.g., metal halides) have been found to improvecell performance for reasons that are not completely understood, andthey are therefore considered to be are a preferred minor ingredient inthe electrode salt mixture. It has been found that the optimalproportions of different salts added to a given electrode mixture varyfrom one cell to the next and may change as the cell is scaled up insize. This optimization process is attainable to anyone skilled in theart of battery development.

A variety of other substances may be added, usually in small amounts(i.e., ˜1-10 m %), to the electrodes to enhance the cell performance.These additives include other metal salts containing the main chargecarrying species (e.g., carbonates, sulfates, nitrates, phosphates, andother oxyanion compounds) as well as various metal oxides (e.g., Al₂O₃),nonmetal oxides, intercalation materials (e.g., carbon or transitionmetal oxides and sulfides), and aliovalent metal salts. Examples of thelatter type of additive include CaCl₂ in LiCl-based electrodes and BaCl₂in NaCl-based electrodes. The beneficial effects of such aliovalentmetal chlorides are believed to be due to an enhancement in the bulkalkali metal cation conductivity due to the creation of metal cationvacancies in the host metal salt crystal structure. For NaCl-basedelectrodes, another additive that was found to greatly enhance electrodeperformance is Al₂O₃. This latter additive is also believed to enhancethe bulk cationic conductivity and therefore this additive is, alongwith BaCl₂, a preferred ingredient in NaCl-based electrodes.

The electrodes are preferably supported as coatings on a suitablesupport or substrate such as carbon, a metal, a metal-carbon composite,or an intercalation compound. Other materials that may be included as anintegral part of the substrate that are beneficial to the cellperformance are silicon, boron, and multi-component compounds or alloyscontaining carbon, silicon, boron, and/or nitrogen (e.g., BN, BC_(x),and BC_(x)N, where x≧1). Anodes are typically supported on carbon, ametal such as nickel or copper, or a metal-carbon composite, whereascathodes may be supported on carbon or some otherelectronically-conducting material that has good intercalationproperties, e.g., MnO₂ or CoO₂. Although most of the Examples describedherein employ carbon-on-metal substrates for both electrodes, it shouldbe noted that a wide variety of electrode configurations are possible inthis invention. For example, both the anode and cathode may consist ofmetal salt-coated carbon electrodes, or the anode may consist of metalsalt-coated carbon while the cathode consists of a metal salt-coatedfirst-row transition metal oxide or some other material with asufficiently high charge storage capacity. Another possibility is thatone or more electrode metal salts may be mixed with a substance capableof intercalation (e.g., carbon), and this mixture may be supported on ametal or carbon substrate.

In addition, to achieve the highest possible specific power density andcycle number, these all-metal salt electrodes should be used withchemically-compatible electrolytes. In this invention, two types ofelectrolytes are employed, i.e., solvent-based and ambient temperaturemolten salt-based. The former are made using well-known batteryelectrolyte fabrication techniques by adding a metal salt containing themain charge-carrying metal cation species to the desired host solvent,preferably one with a wide electrochemical window. Electrolyte solventsthat meet these and numerous other requirements are thionyl chloride(SOCl₂) and sulfuryl chloride (SO₂Cl₂); in addition, since thesesolvents are reducible, they often play a dual role as cathode activematerial, as discussed above. In solvents such as these, it is wellknown that the addition of a third component with Lewis acid charactersuch as AlCl₃ is generally necessary to increase the solubility of themetal salt (which is normally basic) so that the electrolyteconductivity can be made sufficiently high. Well-known examples of metalsalts that contain the metal cation of interest that can also be made tohave a good solubility by adding Lewis acid salts as third componentsare the alkali halides (e.g., LiCl). The Lewis acid salt and metal saltare typically added in a nearly 1:1 molar ratio (e.g., as LiAlCl₄ saltfor LiCl and AlCl₃), but deviations from this composition are possibleand some cases may be desirable to optimize cell behavior.

The (Lewis base) metal salts for the inorganic solvent-based catholytesof this invention are chosen mainly from the metal halides, but othertypes of electrolyte salts (e.g., metal pseudo halides) are possible,and they are given in the Examples. For the present applications, AlCl₃is the preferred Lewis acid salt and is used almost exclusively in thoseExamples that utilized solvent-based catholytes. This preference ofAlCl₃ over other salts with Lewis acid character stems from a number ofpractical considerations; namely, AlCl₃ is relatively inexpensive,nontoxic, easy to purify (or obtain in sufficiently purified form), andhas a fairly low molecular weight. In addition, the solution chemistryof AlCl₃ in oxychloride solvents has been well characterized anddocumented in the research literature. It should be noted, however, thatother slats with Lewis acid character such as PF₆ and AsF₆, many ofwhich are well known and in common use in the battery industry, can beused in place of AlCl₃ with comparable results, and without departing inany way from the spirit and scope of this invention.

For high energy and power density batteries, the sulfur oxychlorides arethe most preferred of all the known reducible inorganic halogen- andchalcogen-containing solvents because of their high cell potentials withrespect to lithium as well as the high exchange current densities thatthey yield. It should be noted, however, that any electrolyte containingone or more oxidizable or reducible halogen- and/or chalgogen-bearingcompounds may be utilized in cells of the design described hereinwithout departing from the spirit and scope of this invention. Examplesof such include those with the general formulas, M_(p)X_(n) orM_(p)Z_(m)X_(n), where M is either a metal (e.g., Ti, V), sulfur, orphosphorus, Z is a chalcogen, and X is a halogen. In addition, theinterhalogens, X_(m)X′_(n) (e.g., ICl₃), and the sulfur oxides, SO₂ andSO₃, may be utilized in a similar capacity. The redox reactions of mostof these compounds are very similar to those of the sulfur oxychloridesand phosphorus chlorides, i.e., these reactions generally involve theuptake or liberation of halide or chalcogen anions, X⁻ and Z²⁻, with theformation of one or more neutral elements or molecules uponelectroreduction. Also, most of these compounds are molecular liquids atroom temperature, and their liquid structures and solution chemicalequilibria with Lewis acid and base salts are known to be very similarto those of the sulfur oxychlorides; these attributes make them wellsuited as electrolyte solvents for rechargeable cells. Moreover, theability of many of these compounds to act as a liquid cathode activematerial in electrochemical cells has been previously demonstrated. U.S.Pat. Nos. 3,926,669, 3,953,229, 3,953,233, 4,012,564, and 4,400,453describe the use of a wide variety of covalent oxyhalide and thiohalidesolvents as cathodes in lithium primary cells.

Several families of low-melting molten salt systems based on AlCl₃ andPCl₅ disclosed herein have been discovered that are promisingelectrolyte solvents for high energy and power density rechargeablecells employing the new electrode design. The liquid structures of thesemolten salts consist mainly of ionic complexes, AlCl₄ ⁻ and PCl₄ ⁺,which are formed by a Lewis acid-base reaction between AlCl₃ and PCl₅.This ionic complex liquid structure is believed to be the origin of thelow melting points, low vapor pressures, and wide liquid temperatureranges, which make them extremely stable solvents for a wide variety ofelectrode salts and well suited for room temperature applications. Inthe AlCl₃—PCl₅ binary, a low-melting eutectic occurs at ˜67 m % AlCl₃ at25° C. A number of related ternaries based on the AlCl₃—PCl₅ binary havealso been developed as electrolyte solvents which includeAlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃. These ternariesform stable liquids at room temperature over a wide range of mixturecomposition. The third components (i.e., PCl₃, POCl₃, and PSCl₃), whichserve to lower the melting point even further, are typically added at aamount<40 m % so that the mixture is a single phase liquid. Theseternaries, which are also believed to consist primarily of ioniccomplexes, can be made ionically conducting in the cation of theelectrode active metal of the cell by adding salts containing thedesired metal cation, e.g., LiCl and LiAlCl₄. Electrical conductivitydata are presented below in Example #1.

In addition, these ambient temperature molten salt electrolytes may,depending on the compounds comprising the electrode solid phases, alsofunction as liquid electrodes since the phosphorus-containing componentsare capable of being oxidized and reduced during cell operation. Forexample, in the AlCl₃—PCl₅—PCl₃ ternary, whereas AlCl₃ is more highlystable with respect to oxidation and reduction during normal celloperation, PCl₃ may reversibly uptake (and/or PCl₅ may release) chlorineduring the discharging and charging of a metal chloride-containingelectrode, as discussed above (“Summary of Invention”). Thus, when thecell chemistry is such that it can also act as an electrode, theAlCl₃—PCl₅—PCl₃ ternary may be regarded as a chlorine reservoir enablingthe reversible dissociation and reformation of solid metal saltelectrodes containing metal chloride. Also, the POCl₃ and PSCl₃components, which, as noted above, have been previously utilized inprimary cells as liquid cathodes, may also assume a similar function incells employing the new electrode design, depending on the electrodecomposition and state of cell charge.

Promising families of cell component material compositions discovered inthe course of this investigation that yield potentially high storagecapacity and high specific energy and power density rechargeablebatteries are summarized in the Claims; more specific examples are givenwithin this disclosure in the Examples. Although the materials listed inthe Claims and Examples provide a good overview of the different typesof chemistries that can be employed in ambient-temperature rechargeablebatteries based on the new cell design, they should not be considered tobe exhaustive.

The overall cell fabrication process from start to finish generallyconsisted of five stages, i.e., I. Starting Materials Preparations, II.Electrolyte Preparations, III. Electrode Substrate Preparations, IV.Electrode Coating Preparations, and V. Cell Assembly. For each stage,those experimental procedures and materials most commonly employedherein are described below in detail. They will henceforth be referredto throughout the Examples for brevity, and any deviations therefromwill be noted as appropriate.

I. Starting Materials Preparations

In all cases, the water used in the preparation of the cells from startthrough finish was purified in the usual manner by deionization anddistillation.

All inorganic compounds (e.g., salts) and solvents (e.g., actonitrile)other than water employed herein were reagent grade of 98%-99.9% purityand purchased from Alfa/Johnson Matthey unless noted otherwise.

Since most of the substances used herein are hygroscopic, most materialshandling procedures were carried out in a dry box, usually in the courseof preparing the cell component materials (i.e., electrodes andelectrolyte). Commonly-used materials handling procedures included thegrinding of solid materials to fine powders with a mortar and pestle.

A number of ternary and quaternary salt compounds were fabricated hereinfor use as electrolyte additives to impart a high ionic conductivity.All fabrication procedures were carried out in an argon-filled dry boxunless noted otherwise. Care was taken to insure that the starting saltswere thoroughly dried prior to mixing. Also, all starting salts wereground to fine powders with a mortar and pestle. The fabricationprocedures for four multi-component salt compounds are given as follows.

LiAlCl₄ was prepared by combining 4.2 g LiCl with 13.3 g AlCl₃ in acovered glass bottle and heating the powder mixture first to 150° C.,where it was held for 30 minutes, then to 200° C. where it was helduntil all the solids had reacted to form a single compound (i.e.,LiAlCl₄). Heating was performed from start to finish using a hot plate.

NaAlCl₄ was prepared by combining 5.8 g NaCl and 13.3 g AlCl₃ in acovered glass bottle and heating to about 250° C. on a hot plate until ahomogeneous single phase liquid had formed. The liquid mixture wascooled to room temperature, and the resulting solid (i.e., NaAlCl₄) wascrushed to a fine powder with a mortar and pestle.

NaAl(OCN)Cl₃ and NaAl(SCN)Cl₃ were prepared in the same manner asdescribed above for NaAlCl₄ starting with, respectively, 6.5 g NaOCN and13.3 g AlCl₃, and 8.1 g NaSCN and 13.3 g AlCl₃.

In many of the cells, carbon was used as an integral electrodecomponent, e.g., as a substrate or as an electrode active material.Unless stated otherwise, this carbon was in the form of fiber clusterand was manufactured by Hercules, Inc. (Type AS4-6-3K). In all cases,the fibers were cleaned prior to use by soaking them in concentratedH₂SO₄ followed by a thorough rinsing with water.

For all the carbon-on-nickel substrates, nickel metal supports were cutfrom nickel net with a thickness of about 0.003 mm which was woven from0.17 mm diameter wires. This nickel net was manufactured by Exmet Corp.(Mesh 3NI5.5-4/0A). In all cases, the nickel net was cleaned prior touse by soaking in dilute HNO₃ followed by a thorough rinsing with water.

II. Electrolyte Preparations

The electrolytes were prepared from start to finish in a dry box with anargon atmosphere unless stated otherwise. Two main types of electrolyteswere employed, i.e., solvent-based and molten-salt based. Their commonpreparation procedures are described below.

A. Solvent-Based

The solvent-based electrolytes used either SOCl₂ or SO₂Cl₂ as thesolvent. These solvent-based electrolytes were made by dissolvingstoichiometric amounts of the desired solutes in the specified nominalconcentrations (by mole fraction) into the solvent. The ingredients werecombined at room temperature unless stated otherwise. Both SOCl₂- andSO₂Cl₂-based electrolytes were typically made in ˜1 mole lots (bysolvent). The exact recipes varied from one cell to the next and aregiven in the Examples.

B. Molten Salt-Based

The molten salt electrolytes are based on the ternaries,AlCl₃-PCl₅-PCl₃, AlCl₃-PCl₅-POCl₃, and AlCl₃-PCl₅-PSCl₃. The preparationprocedures for those that were most commonly employed are given below:

i) AlCl₃-PCl₅-0.3 PCl₃

A molten salt mixture with the above nominal composition was made asfollows. Small lots (˜38 g) were prepared by combining 13.3 g AlCl₃ with20.8 g PCl₅ in a covered glass bottle and heating to 170° C. using a hotplate until the mixture became homogeneous. This mixture was then cooledto about 40° C. and 50 g PCl₃ was added. These ingredients were mixed,heated to 50° C., and held for two hours. After this mixture was allowedto equilibrate, it was found that a liquid consisting of two distinctphases had formed. The top liquid consisted mostly of undissolved PCl₃and was removed entirely by skimming it off the top. The liquid that hadsettled to the bottom consisted of AlCl₃ and PCl₅ present at a 1:1 molarratio in which PCl₃ was present at saturation, giving a molar ratio ofAlCl₃, PCl₅, and PCl₃ estimated at about 10:10:3 based on the amount ofPCl₃ in the top liquid. This bottom liquid constituted theAlCl₃-PCl₅-0.3 PCl₃ solvent.

This molten salt mixture was used either alone or as an electrolytesolvent for a variety of solutes, e.g., LiAlCl₄ and NaAlCl₄. Larger lots(˜200-250 g) of AlCl₃-PCl₅-0.3 PCl₃ solvent were prepared as necessaryin a manner very similar to that described above by proportionallyscaling up the quantities of all the starting ingredients.

Throughout the Examples, this electrolyte solvent, prepared as describedabove, will be referred to as “AlCl₃-PCl₅-0.3 PCl₃.”

ii) AlCl₃-PCl₅-0.3 R(R=POCl₃ or PSCl₃)

These molten salt mixtures with the nominal composition given above wereprepared in lots of ˜39 g each as described above for AlCl₃-PCl₅-PCl₃except that either POCl₃ or PSCl₃ was substituted for PCl₃.

The phase equilibria of these ternaries appear to be similar to that ofAlCl₃-PCl₅-PCl₃; adding an excess of either POCl₃ or PSCl₃ to mixturesof AlCl₃ and PCl₅ also results in the formation of a two-phase mixture,the bottom liquid consisting of AlCl₃ and PCl₅ present at a 1:1 molarratio, with POCl₃ or PSCl₃ present at saturation. The amount of POCl₃and PSCl₃ present at saturation in these mixtures is uncertain but wasestimated at around 30 m % (±3 m %) based on the amount of top liquid.In both cases, the bottom liquid constituted the AlCl₃-PCl₅-0.3 Rsolvent.

Throughout the Examples, these electrolyte solvents, prepared asdescribed above, will be referred to as “AlCl₃-PCl₅-0.3 POCl₃” and“AlCl₃-PCl₅-0.3 POCl₃.”

III. Electrode Substrate Preparations

Most of the substrates were of the carbon-on-metal type, and the metalsupport material was typically nickel. Five main methods were developedherein for the application of carbon to a metal support. In the firstmethod (Type I), carbon fiber cluster are wound around the metal supportso that it is completely covered from both sides (0.020-0.025 g/cm²). Inthe second method (Type II), the carbon is applied to the metal support(0.010-0.012 g/cm²) by using a carbon fiber powder-Teflon paste. In thethird method (Type III), the carbon is applied to the metal support(0.010-0.012 g/cm²) by using a carbon fiber powder-polypropylene oxide(PPO) paste. In the fourth method (Type IV), the carbon is dispersed asa thin layer of short carbon fibers by applying them to the metalsupport (0.027 g/cm²) by using a carbon fiber-PPO-acetonitrile slurry.In the fifth method (Type V), the carbon is applied to the metal as aslurry of carbon powder-PPO-acetonitrile.

It should be noted that in the Type II through V methods describedherein, the amounts of carbon applied to the metal supports can befurther reduced as necessary and desired from those given in the recipesprovided herein by process optimization. Substrate fabricationprocedures such as Types II through V are therefore generally morepreferred for the design of larger prototype cells or batteries forelectric vehicle battery applications in which a reduction in weight ofall electrode active materials is crucial.

The above-described methods were the primary ones employed herein forthe application of carbon to electrode assemblages as a distinctsubstrate phase. Other methods were also devised for the application offinely -dispersed carbon to electrode assemblages; in these methods, thecarbon was made into a paste by mixing it with both a binder and anelectrode active metal salt. These methods are described in more detailin the Examples.

Unless stated otherwise, all substrate preparations were carried out inair except for those treatments carried out above room temperature suchas drying and annealing. Detailed descriptions of the preparationprocedures for the most commonly used substrates are given below.

A. Carbon-on-nickel, 4×10 mm, Type I (wound carbon fibers)

This carbon-on-nickel substrate was prepared as follows. First, thenickel for the substrate and lead to the external circuit was cut in onecontinuous piece from nickel net; a 4×10 mm section formed thesubstrate, and a thinner rectangular “tail” 2 mm wide was centered onone of the 4 mm edges. The tail was used as the lead; about 10 mm of thetail was left as net, and thereafter, nickel wires for use asconnections to the external circuitry were freed from the net byremoving the cross wires. The carbon was applied by densely windingcarbon fibers around the 4×10 mm nickel net rectangle, making certainthat each side was thoroughly covered with carbon fiber so that thenickel metal would never be exposed to the electrolyte during celloperation. A carbon fiber was also wound around enough of the thinrectangle comprising the lead so as to protect all parts of the leadthat would be in the cell housing from possible exposure to theelectrolyte. The total weight of wound carbon fibers on each substratetypically was 0.008-0.010 g, i.e., (0.02-0.025 g)/cm².

Throughout the Examples, this substrate type, prepared as describedabove, will be referred to as “carbon-on-nickel substrate, 4×10 mm, TypeI (wound carbon fiber).”

B. Carbon-on-platinum, 4×10 mm, Type I (wound carbon fibers)

This carbon-on-platinum substrate was prepared as follows. A 4×10 mmpiece of Pt foil was used as the substrate; a 10 mm long Pt wire (0.4 mmdiameter) was used as the lead. This lead was spot welded onto thecenter of one of the 4 mm edges. The carbon fiber was applied by denselywinding carbon fibers around the 4×10 mm Pt foil rectangle using exactlythe same procedure as described above for the carbon-on-nickelsubstrate, 4×10 mm, Type I. The total weight of wound carbon fibers oneach substrate was typically about 0.008-0.010 g, i.e.,(0.02-0.025)g/cm².

Throughout the Examples, this substrate type, prepared as describedabove, will be referred to as “carbon-on-platinum substrate, 4×10 mm,Type I (wound carbon fibers).”

C. Carbon-on-nickel, 4×10 mm, Type II (carbon-Teflon paste)

This carbon-on-nickel substrate was prepared as follows. About 10 g ofcarbon fibers were cut to 5 mm lengths which were then combined with 0.5g LiCl and 10 ml water. This mixture was heated in air at a rate ofabout 5° C./minute from 50° C. to 250° C., held for two hours, andcooled to room temperature. Afterwards, this mixture, which consistedmostly of carbon and LiCl, was heated to about 1000° C. with a propaneflame, cooled to room temperature, and then crushed to a fine powder.The excess LiCl was washed away with water, and the remaining material,which consisted mostly of carbon, was mixed thoroughly with aTeflon-water paste containing about 0.2 g Teflon.

A 4×10 mm nickel net was prepared as described above for thecarbon-on-nickel substrate, 4×10 mm, Type I. About 0.006-0.01 g of thepaste prepared as described above was applied evenly to both sides ofthe nickel net then smoothed by squeezing between a glass roller andglass plate. This carbon-on-nickel substrate assemblage was heated inair to 150° C. and held for two hours, heated thereafter in vacuum to200° C. and held for two hours, cooled to room temperature, placed in avacuum-sealed Pyrex glass tube, and given a final heat treatment at 500°C. for one hour. The total amount of carbon on the substrate once allthe preparations were complete was about 0.004-0.008 g, i.e., (0.01-0.02g)/cm².

Throughout the Examples, this substrate type, prepared as describedabove, will be referred to as “carbon-on-nickel substrate, 4×10 mm, TypeII (carbon-Teflon paste).”

D. Carbon-on-nickel, 4×10 mm, Type III (carbon-polypropylene oxidepaste)

This carbon-on-nickel substrate was prepared as follows. Carbon fiberpowder was prepared in a lot of about 10 g as described above for thecarbon-on-nickel substrate, 4×10 mm, Type II. After the excess LiCl wasremoved in the final step, the remaining material, which consistedmostly of carbon, was allowed to dry under ambient conditions. A pastewas made by combining 5.0 g of the carbon fiber powder with 2.0 g of abinder which consisted of one part by weight of polypropylene oxide witha molecular weight of about 8,000,000 g/mole (i.e., PPO_(8,000,000)) andone part by weight of acetonitrile. (The binder was made in 100 g lotsby combining 50 g PPO_(8,000,000) with 100 g acetonitrile, allowing thePPO_(8,000,000) to dissolve completely, then evaporating 50 g of theacetonitrile solvent.)

A 4×10 mm nickel net was prepared as described above for thecarbon-on-nickel substrate, 4×10 mm, Type I. About 0.006-0.01 g of thepaste prepared as described above was applied evenly to both sides ofthe nickel net then smoothed by squeezing between a glass roller andglass plate. This carbon-on-nickel substrate assemblage was heated invacuum to 150° C., held for about four hours, cooled to roomtemperature, placed in a vacuum-sealed Pyrex glass tube, heated slowlyfrom 100° C. to 500° C., and held for four hours. The total amount ofcarbon on the substrate once all the preparations were complete wasabout 0.004-0.008 i.e., (0.010-0.020 g)/cm².

Throughout the Examples, the substrate type, prepared as describedabove, will be referred to as “carbon-on-nickel substrate, 4×10 mm, TypeIII (carbon-PPO paste).”

E. Carbon-on-nickel, 50×70 mm, Type IV(carbon-acetonitrile-polypropylene oxide slurry)

This carbon-on-nickel substrate was used in the jelly-roll test cell(see below) and was prepared as follows. First, the nickel for thesubstrate and leads to the external circuit was cut in one continuouspiece from nickel net; a 50×70 mm section formed the substrate, and 5rectangular “tails” about 2 mm wide were evenly distributed along theentire length of one of the 50 mm edges from one end to the other. Fivenickel wires spaced about 12-13 mm apart for use as connections to theexternal circuitry were freed from the net by removing the cross wiresfrom the tails. This nickel net was coated evenly on both sides with acarbon-PPO-acetonitrile mixture which was prepared as follows.

Ten grams of carbon fibers were cut to 1 mm lengths and mixed with 40 gPPO-acetonitrile binder which was prepared in ˜100 g lots by combining 5g PPO_(8,000,000) with 100 g acetonitrile. This mixture, which was inthe form of a thin slurry, was applied to the nickel net by immersing ituntil thoroughly covered and allowing it to dry under ambient conditionsfor a few minutes. This process was repeated several times until theamount of carbon deposited on the net was about 1.0 g. Thiscarbon-on-nickel substrate assemblage was dried in air for about 2 hoursthen heated in vacuum for 4 hours at 150° C. This assemblage was cooledto room temperature, placed in a quartz tube stuffed at the open endwith glass paste paper, and placed in a furnace. A nitrogen atmospherewas introduced, and the assemblage was heated at 5° C./minute from 100°C. to 300° C., held for 2 hours, heated at 5° C./minute to 600° C., andheld for 5 hours. Afterwards, the assemblage was cooled slowly to roomtemperature in nitrogen.

The above-described procedure for applying the carbon to the nickel netswas devised for this substrate to minimize the total amount of materialdeposited on the nickel nets so that the final electrode assemblageswould be as flexible as possible and therefore easier to wind into ajelly-roll.

Throughout the Examples, this substrate type, prepared as describedabove, will be referred to as “carbon-on-nickel substrate, 50×70 mm,Type IV (carbon-acetonitrile-PPO slurry).”

F. Carbon-on-nickel, 50×70 mm, Type V (carbon-acetonitrile-polypropyleneoxide slurry)

This carbon-on-nickel substrate, which consists mostly of carbon fabric,was also used in the jelly-roll test cell (see below) and was preparedas follows. First, a 50×70 mm rectangle of carbon fabric, 0.95 g, i.e.,0.027 g/cm² (Zoltek, Inc., Panex®30 fabric Pw06) was cleaned by soakingit in concentrated H₂SO₄ for about 10 hours and rinsing it thoroughlywith water. This carbon fabric rectangle was treated further by heatingit with a propane flame to around 1200° C.; this treatment served todrive off impurities and also smoothed the surfaces of the carbon fabricby burning off all the tiny fibers sticking out of the surface.

Five nickel wires which served as the leads to the external circuit wereaffixed to the carbon fabric as follows. These wires, which werearranged in parallel and spaced about 8 mm apart with the first andfifth wires each about 9 mm away from the nearest edge, were tightlysewn or woven into the carbon fabric rectangle along its length (i.e.,70 mm) starting from one 50 mm edge and ending at the other. From thelatter 50 mm edge, at least 10 cm of free nickel wire was left for eachlead to be used for connections to the external circuitry. During theweaving process, great care was taken to insure that the carbon fabricand nickel wires made excellent contact. To further improve theelectrical connections and to prevent the nickel wires from beingexposed to the electrolyte in the cell, all nickel wires surfaces andgaps between the nickel wires and carbon fabric were covered or filledin with a carbon-PPO-acetonitrile slurry which was prepared as follows.

The carbon, which was in the form of a powder, was prepared in a lot ofabout 10 g as described above in Part C for the carbon-on-nickelsubstrate, 4×10 mm, Type II. After the excess LiCl was removed in thefinal step, the remaining material, which consisted mostly of carbon,was allowed to dry under ambient conditions. A paste was made bycombining 5.0 g of the carbon fiber powder with 5.0 g of anacetonitrile-polypropylene binder which was prepared in ˜110 g lots bycombining 100 g acetonitrile with 10 g PPO_(8,000,000). The mixture,which was in the form of a thin slurry, was applied to all exposednickel wire surfaces and gaps between the nickel wires and carbon fabricas described above. The total amount of slurry applied to the substratewas about 0.5 g.

Once the slurry was allowed to dry, the substrate assemblage was heatedin vacuum to 150° C. and held for two hours. This assemblage was cooledto room temperature, placed in a vacuum-sealed quartz tube, heated at 5°C./minute from 50° C. to 550° C., held for 5 hours, and cooled slowly toroom temperature.

Throughout the Examples, this substrate type, prepared as describedabove, will be referred to as “carbon-on-nickel substrate, 50×70 mm,Type V (carbon-acetonitrile-PPO slurry).”

IV. Electrode Coating Preparations

The processing procedures are highly dependent on the types of electrodeactive materials employed, but most of them fall into one of two maincategories, i.e., i) deposition from solution and ii) paste. Theseprocedures are described in more detail below. Unless stated otherwise,all electrode processing procedures were carried out in a dry box withan argon atmosphere except for those treatments carried out above roomtemperature such as drying and annealing.

A. Solution Deposition

In this technique, a substrate is coated to the desired total weight ofa given salt mixture (e.g., 0.2 LiCl-0.8 CaCl₂) by repeatedly immersingit into a solution containing the salts in the specified proportions andbaking it between immersions. For most of the Examples described hereinusing solution deposition, the solvent was water, but occasionally,other solvents such as acetonitrile were used, depending on thecompositions of the electrode active materials.

The common procedures used for the preparation of electrode coatingsusing solution deposition are as follows. First, a starting solution ofthe salts was prepared. (The starting solution compositions varied withboth substrate size and electrode active material composition and aregiven in the Examples.) The immersion procedure consisted of holding oneor both sides of the substrate in the solution, removing it from thesolution, and allowing it to dry under ambient conditions. The amount ofsalt deposited during an immersion, which generally increases withsolution concentration, was controlled by adjusting the concentration ofthe salts in the starting solution. Typically, for the first immersion,the substrate was totally covered with the starting solution and heldfor a few seconds. For later immersions, the amount of salt deposited onthe substrate was “fine tuned” by diluting the solution as necessary ateach stage. As the coating was being built up on the substrate, however,care had to be taken to prevent the already-deposited salt fromre-dissolving in solution; this phenomenon was especially problematic atlater stage immersions because the starting solution had been diluted towell below its original concentration. Therefore, for later stageimmersions using highly diluted salt solutions, only the corners of thesubstrate (or tips in the case of carbon fiber substrates) were immersedin the solution, and natural capillary action was relied upon to drawthe solution to the other regions of the substrate.

After each immersion, the substrate was baked. This baking procedure wasnecessary to insure that all the solvent had been driven off and tomonitor the amount of material deposited at a given stage. The bakingprocedure performed after each immersion typically consisted of heatingthe coated substrate in air or in vacuum to drive off the solvent and,in some cases, to effect a desired chemical reaction (e.g., seeelectrode (ii) below). The baking times and temperatures varied with thetypes of coating and substrate materials used and are given in theExamples.

The immersion-baking cycle was repeated as necessary until the desiredtotal weight of the salt mixture on the substrate was reached. Unlessstated otherwise, the salt mixture was coated evenly on both sides ofthe substrate; for carbon fiber substrates, the salt coating was appliedevenly around the circumference along the length of the fiber. Once thesalt mixture had been built up to its desired amount, the coatedsubstrate was typically given a final baking as described in more detailin the Examples. Also, it was generally given a final higher-temperatureannealing to make certain that the coating was homogeneous in boththickness and composition and that a good bond had formed between thecoating and the substrate. The final baking and annealing schedules aregiven in the Examples.

The preparation procedures for a number of commonly-used electrodesprepared by solution deposition are given below. These preparationprocedures apply to all 4×10 mm carbon-on-nickel substrates (i.e., TypeI through IV).

i) 0.2 LiCl-0.8 CaCl₂, 4×10 mm, carbon-on-nickel

For this electrode, a 4×10 mm carbon-on-nickel substrate was coated tothe desired total weight of LiCl and CaCl₂ by the solution techniquedescribed above. The starting solution consisted of LiCl and CaCl₂present at a molar ratio of about 1:4 which was prepared by dissolving2.52 g LiCl and 26.6 g CaCl₂ in 50 ml water. The baking procedureperformed after each immersion consisted of heating the coated substratein air at a rate of about 5° C./minute from 50° C. to 150° C., holdingit for two hours, drawing a vacuum, heating it to 200° C., holding itfor two hours, then cooling it back to room temperature. This bakingprocedure was necessary to insure that all the water had been driven offand was such that the nickel would not be attacked by oxygen. Theimmersion-baking procedure was repeated as necessary until the totalweight of the LiCl-CaCl₂ salt mixture on the substrate was about 0.02 g.For the final baking, the electrode assemblage was inserted into a Pyrextest tube in an argon-filled dry box and glass paste paper was tightlystuffed into the open end.

As a final step, the electrode assemblage prepared as described abovewas inserted into a Pyrex glass tube, and care was taken to insure thatit did not touch the glass walls. The tube was vacuum-sealed and heatedto 250° C., heated thereafter at a rate of 5° C./minute up to 500° C.,and held for 30 minutes. This step was necessary to make certain thatthe coating was homogeneous in both thickness and composition and that agood bond had formed between the coating and the substrate.

Throughout the Examples, this electrode, prepared as described above,will be referred to as “electrode type 0.2 LiCl-0.8 CaCl₂, 4×10 mm,carbon-on-nickel.”

ii) 0.5 NaCl-0.25 Al₂O₃-0.25 BaCl₂, 4×10 mm, carbon-on-nickel

An electrode with the nominal composition given above was prepared asfollows. NaCl, AlCl₃, and BaCl₂ were combined in a 2:2:1 molar ratio bydissolving 5.8 g NaCl, 13.3 g AlCl₃, and 10.4 g BaCl₂ in water as asaturated solution at 40° C. (To make this solution, water was added tothe salt mixture while stirring with a magnetic stirrer on a hot plateuntil all the solids had dissolved.) This salt mixture was depositedfrom solution as a coating on a 4×10 mm carbon-on-nickel substrate usingthe solution technique described above. The baking procedure performedafter each immersion consisted of first drying the coated substrate byheating in air at a rate of about 5° C./minute from 50° C. to 100° C.and holding for one hour. Then, the coated substrate was heated to 190°C., held for two hours, heated thereafter at a rate of 10° C./minute to850° C. and held for 30 minutes. This baking procedure served to driveoff all the water and also insured the complete conversion of AlCl₃ toAl₂O₃. The immersion-baking procedure was repeated as necessary untilthe total weight of the salt coating was about 0.025 g.

Throughout the Examples, this electrode, prepared as described above,will be referred to as “electrode type 0.5 NaCl-0.25 Al₂O₃-0.25 BaCl₂,4×10 mm, carbon-on-nickel”.

B. Paste

For some of the cells, the electrode coatings were applied as pastes.This technique was most often used for water-insoluble electrode activematerials (e.g., metal fluorides, transition metal oxides, and carbon).The recipes for the pastes varied widely with electrode active materialcomposition, but typically, they were made by combining fine powders ofthe metal salts and other solid phase (e.g., carbon) present in thespecified proportions with small amounts of a binder or vehicle.

The most commonly used binder was one part by weight polypropylene oxidewith a molecular weight of about 8,000,000 g/mole (i.e.,PPO_(8,000,000)) dissolved in 100 parts by weight acetonitrile. Thisbinder was produced in ˜100 g lots by combining 1 g PPO_(8,000,000) with100 g acetonitrile. Unless stated otherwise, this binder was used forthe fabrication of electrode active material pastes and will be referredto as “acetonitrile-01 PPO_(8,000,000) binder.”

Unless stated otherwise, the paste was applied evenly on both sides ofthe substrate; for carbon fiber substrates, the paste was applied evenlyaround the circumference along the length of the fiber. For allsubstrates except carbon fibers, the paste was smoothed by squeezing thecoated substrate between a glass roller and a glass plate. The electrodeassemblage was then given a final heat treatment which typicallyconsisted of a drying procedure followed by a higher-temperature anneal.These final heat treatments varied with the types of materials in theelectrode assemblage and are given in the Examples.

The preparation procedures for a number of commonly-used electrodesprepared as paste coatings are given below. These preparation proceduresapply to all 4×10 mm carbon-on-nickel substrates (i.e., Type I throughIV).

i) 0.8 Li₂O-0.2 Li₂CO₃, 4×10 mm, carbon-on-nickel

A mixture of Li₂O and Li₂CO₃ with the nominal composition given abovewas prepared by partially decomposing 14.2 g Li₂CO₃ as follows. 14.2 gLi₂CO₃ was placed in a quartz test tube, heated in air to 500° C., andheld for about 5 hours. Then, the temperature was increased to 1310° C.(the decomposition temperature of Li₂CO₃) and the Li₂CO₃ was held for atime sufficient to drive off enough CO₂ so that the desired molefraction of Li₂O (i.e., y=0.8) would be obtained. At this temperature,the rate of Li₂CO₃ decomposition to Li₂O and CO₂ is sufficiently high,and the amount of CO₂ driven off as a function of heating timedetermines the relative amounts of Li₂O and Li₂CO₃ present in themixture. For the Li₂O-Li₂CO₃-containing electrodes used in this study,heating times on the order of 30 to 120 minutes were used. For thiselectrode salt mixture, the starting Li₂CO₃ was held at 1310° C. for atotal heating time of one hour giving a mixture of about 2.84 g. Li₂CO₃and 4.6 g Li₂O as calculated from the weight loss (i.e., 6.8 g).

After the Li₂O-Li₂CO₃ mixture had cooled to room temperature, it wastransferred to a dry box, crushed to a fine powder with a mortar andpestle, and combined with 1.0 g of the acetonitrile-01 PPO_(8,000,000)binder prepared as described above in this section. Approximately equalamounts of this paste were applied evenly to each side of a 4×10 mmcarbon-on-nickel substrate; the total amount ranged from about 0.001 gto 0.02 g, depending on the cell. The paste was smoothed by squeezingbetween a glass roller and a glass plate. The electrode assemblage washeated to 150° C. in air, held for two hours, cooled to roomtemperature, placed in a large Pyrex tube which was vacuum-sealed,heated to 600° C., held for two hours, and cooled to room temperature.

Throughout the Examples, this electrode, prepared as described above,will be referred to as “electrode type 0.8 Li₂O-0.02 Li₂CO₃, 4×10 mm,carbon-on-nickel.”

ii) 0.4 LiCl-0.48 Li₂O-0.012 Li₂CO₃, 4×10 mm, carbon-on-nickel

This electrode consists of a salt mixture in which the LiCl is presentat 40 m % and the salt mixture, 0.8 Li₂O-0.2 Li₂CO₃, is present at 60 m%. The starting 0.8 Li₂O-0.02 Li₂CO₃ mixture was prepared by decomposing14.2 g Li₂CO₃ as described above for the electrode type 0.8 Li₂O-0.2Li₂CO₃, 4×10 mm, carbon-on-nickel. After it had cooled to roomtemperature, it was transferred to a dry box, crushed to a fine powderwith a mortar and pestle, and combined with 5.43 g LiCl. A paste wasmade with this 0.4 LiCl-0.48 Li₂O-0.12 Li₂CO₃ powder mixture by adding1.0 g of the acetonitrile-01 PPO_(8,000,000) binder. Approximately equalamounts of this paste were applied evenly to each side of a 4×10 mmcarbon-on-nickel substrate; the total amount ranged from about 0.01 g to0.03 g, depending on the cell. The paste was smoothed by squeezingbetween a glass roller and a glass plate and given the same final heattreatment as described above for the electrode type 0.8 Li₂O-0.2 Li₂CO₃,4×10 mm, carbon-on-nickel.

Throughout the Examples, this electrode, prepared as described above,will be referred to as “electrode type 0.4 LiCl-0.48 Li₂O-0.12 Li₂CO₃,4×10 mm, carbon-on-nickel.”

V. Cell Assembly

Several types of testing or prototype cells were employed in this studywhich differ according to their size and shape. The test cell designsemployed herein are all parallel plate-type (including the Tiny Celldesign described below) except for one larger cell which is a jelly-rolltype. A wide range of cell sizes was employed with electrode crosssectional areas ranging from about 0.1 to 35 cm². This size rangeenabled an assessment of the ability of certain promising cell materialcompositions to be scaled up to larger cell sizes, but it should benoted that these test cells were designed primarily for a preliminaryevaluation of cell component materials properties in rechargeable cells.These test cell designs were not optimized as far as packaging weight,and volume are concerned. For example, in most of the cell designs, theamount of electrolyte added far exceeds the actual amount between theelectrodes; hence, for each Example, the amount of working electrolytebetween the electrodes is listed to provide an estimate of the minimumamount necessary to construct a rechargeable cell of a given size withgiven amounts of electrode active materials. Although cell assembly wasnot the main concern, it can be readily appreciated that the fullconsideration thereof by those skilled in the art of batteryconstruction can be easily and fruitfully applied to the construction ofbatteries based on the new types of cell component materials disclosedherein.

For all the parallel plate designs, the working electrode activematerial was considered to be all anode and/or cathode active materialpresent between the electrodes; for each electrode, this amount wasgenerally about half the total material applied to the substrate. Forthe jelly-roll design, the total working electrode active materialincluded all electrode active material applied to both sides of thesubstrates. These assumptions were made both in the calculations ofdischarging Coulombic capacity given in some of the Examples and in theamounts of working anode and cathode active materials listed in all theExamples.

The physical characteristics and fabrication procedures of the celldesigns most commonly used in this study are described below. The cellswere housed in Pyrex glass tubes which were found to be more thansatisfactory as they could withstand the moderate gas pressure buildupthat sometimes occurred for cell designs employing SOCl₂ and SO₂Cl₂catholytes. Unless noted otherwise, all cell assembly procedures werecarried out in an argon-filled dry box except for those treatmentscarried out above room temperature such as drying and annealing.

A. Tiny Cell (10 mm carbon fiber cluster substrate)

For this cell, a substrate-lead assemblage was constructed for eachelectrode as follows. A 50 mm long Pt wire 0.4 mm in diameter was joinedto a 20 mm long carbon fiber cluster about 1-2 mm in diameter. Thisjoining operation was performed by placing one end of the Pt wire nextto one end of the carbon fiber cluster with an overlap length of about10 mm. A piece of Pt wire 0.1 mm in diameter was tightly wrapped andtwist tightened around the two materials along the 10 mm region ofcontact. The Pt wire-carbon fiber cluster assemblage was inserted into athin glass tube about 10 mm long with an inner diameter of about 2 mm.The region of contact between the Pt wire and carbon fiber cluster wascovered by the glass tubing, and the remaining 10 mm of carbon fiberbunch was uncovered. At the other end, a glass-to-metal seal was madebetween the glass tube and Pt wire by heating the glass until moltenwith an oxygen-acetylene flame. In order to bridge all fine carbonfibers, the 10 mm carbon fiber cluster was immersed into thePPO_(8,000,000)-acetonitrile (1:10) solution and dried about 2 hours inair, then heated by an oxygen-acetylene flame (˜700° C.) a few minutes.

Substrate-lead assemblages fabricated as described above were used forboth electrodes. The entire 10 mm length of uncovered carbon fiberssticking out of the glass tube was used as the electrode substrate.Electrode coatings were more often applied as salt solutions but wereapplied as pastes when necessary, depending on the chemical compositionsof the electrode active materials. For the solution deposition method,the desired weight of salt was built up by repeated immersion-bakingsteps; if, at any stage of deposition, the amount of salt exceeded thedesired weight, the electrode assemblage was discarded and thedeposition process was started over again on a new substrate-leadassemblage.

The cell was assembled as follows. The two electrode assemblagesprepared as described above were joined at the bottom near thecarbon-platinum contact by heating the glass tubes until softened withan oxygen-acetylene flame and affixing them along their entire lengthsby joining them at the top with a metal or carbon clamp. This operationwas carried out so that the two carbon fibers would be parallel to oneanother with a gap greater than about 0.5 mm but not exceeding 1 mm. Thetwo electrode assemblages were placed into a 100 mm long Pyrex glasstube closed at one end with a 6 mm inner diameter so that the carbonfiber tips were about 10 mm from the bottom of the tube. Anoxygen-acetylene flame was used to heat all the glass tubes until theywere softened so that they would be joined along their entire lengthsand the positions of the electrode tubes would be permanently fixedwithin the cell. This arrangement left openings at the top and conduitsalong the sides of the Pyrex tube leading to the bottom which weresufficiently wide so that electrolyte could be easily injected insidethe cell at a later stage. Afterwards, the clamp was removed and theentire cell assemblage was annealed by heating in air from 200° C. to500° C. at a rate of 10° C./minute, held for two hours, then slowlyvacuum-cooled to room temperature. As a final step, the electrolyte wasinjected into the cell from a top opening, the cell was shaken until theelectrolyte had settled to the bottom so that the gap between the twoelectrodes was completely filled with electrolyte, and all top openingswere sealed with an oxygen-acetylene flame. The amount of electrolyteinjected into the cell was typically about 1.0 g; the amount ofelectrolyte that settled between the electrodes was estimated at about0.005-0.006 g.

Throughout the Examples, this cell type, prepared as described above,will be referred to as “Tiny Cell.”

B. Parallel Plate, 4×10 mm

This cell was assembled as follows. A Pyrex glass tube with an innerdiameter of 5 mm was used to house the cell. Two holes were made onopposite sides of the tube. The anode and cathode assemblages weresupported on 4×10 mm substrates. Depending on their chemicalcompositions, the electrode active materials were applied either as saltsolutions or as pastes. The electrode assemblages were carefullyinserted into the tube. Care was taken to insure that the two electrodeswere parallel to one another with a gap of about 1 mm. The leads on eachelectrode were threaded through the two holes to the outside of theglass tube. The two holes were sealed in a manner that depended on thetype of metal used. For substrate-lead metals such as nickel or copper,the holes were sealed with epoxy which was allowed to set for two hours.For platinum, the holes were sealed by heating the area with anoxygen-acetylene flame until molten to form a glass-to-metal seal. Oneend of the glass tube was sealed at a distance of about 15 mm from theelectrodes. The electrolyte was injected into the tube and as a finalstep, the entire cell assemblage was sealed at the top. The amount ofelectrolyte injected into the cell was typically about 1.0 g; the amountof electrolyte that settled between the electrodes was estimated atabout 0.05-0.06 g.

Throughout the Examples, this cell type, prepared as described above,will be referred to as “Parallel Plate, 4×10 mm.”

C. Parallel plate, 30×70 mm

This cell was assembled using procedures similar to those of the 4×10 mmparallel plate cell described above. A 150 mm long Pyrex glass tube withan inner diameter of 50 mm was used to house the cell. One end of thetube was sealed with an oxygen-acetylene flame, and two holes were madeon opposite sides of the tube 10 mm from the sealed end. Anode andcathode assemblages were prepared from substrates with cross sectionalareas of 30×70 mm. Electrode coatings were applied either from solutionor as pastes. A sandwich was made by inserting between the electrodesthree pieces of glass paste paper about 0.12 mm thick which served as aseparator. This sandwich was covered with two glass slides, and theentire ensemble was affixed by wrapping it tightly with a glass fiber.The glass paste paper and glass slide parts were all cut to the samecross sectional area as the electrodes (i.e., 30×70 mm).

The electrode sandwich was carefully inserted into the glass tube cellhousing and the nickel leads on each electrode were threaded through thetwo holes to the outside. The cell was placed in a horizontal positionsuch that one hole was on top and the other was on the bottom. In thishorizontal position, the sandwich was placed as close to the bottom aspossible, taking care that is was parallel to the tube side walls. Thecell was annealed by heating it slowly in a nitrogen atmosphere from 50°C. to 450° C., holding it for five hours, then cooling it slowly to roomtemperature. The two holes were sealed with epoxy which was allowed toset for two hours. About 25 g of electrolyte was carefully injected intothe tube from the open end, taking care to keep the neck of the tube asclean and unclogged as possible. As a final step, the glass tube cellhousing was trimmed down to about 100 mm, and the entire cell assemblagewas sealed at the open end an oxygen-acetylene flame. The cell was keptin a horizontal position so that the entire space between the electrodesinside the sandwich would always be filled with electrolyte.

Throughout the Examples, this cell type, prepared as described above,will be referred to as “Parallel Plate, 30×70 mm.”

D. Jelly-roll (carbon-on-nickel substrate, 50×70 mm, Type IV)

For this test cell, the electrodes were typically supported oncarbon-on-nickel substrates, 50×70 mm, Type IV. However,carbon-on-nickel Type IV substrates of other sizes, e.g., 40×50 mm, wereused occasionally; these substrates were prepared in a manner verysimilar to that of the carbon-on-nickel substrates, 50×70 mm, Type IV.Depending on their chemical compositions, the electrode active materialswere applied either as salt solutions or as pastes.

The cell was assembled as follows. An anode-separator-cathode-separatorsandwich was made from the anode and cathode assemblages by insertingtwo pieces of glass paste paper between the electrodes and stacking twomore pieces of glass paste paper on top of the cathode. The glass pastepaper separators were all cut from glass paste paper about 0.12 mm thickto the same cross sectional area as the electrodes. The anode andcathode assemblages were arranged in the sandwich so that the two setsof five lead wires (i.e., one set on each electrode) were at oppositeends.

A glass tube 75 mm in length with inner and outer diameters of 2 mm and6 mm, respectively, was used as the center rod for winding the sandwichinto a jelly-roll; this tube was also used as a conduit or feed-throughfor the five cathode lead wires. The glass tube was affixed along one ofthe 70 mm edges of the sandwich on the separator side with one end flushwith the sandwich edge perpendicular to the cathode lead wires. Thisoperation was carried out by twist-tightening the tube to the sandwichedge with glass fibers along its length and feeding the corner cathodelead wire through the tube. As the sandwich was wound tightly around theglass tube, the remaining cathode lead wires were fed one-by-one throughthe tube; this operation served to affix the sandwich more securely tothe tube and also enabled the cathode lead wires to be fed safely to thetop of the rolled cell without any electrical contact with the anode.After the rolling operation was complete, the cathode lead wires weretwisted together. The anode wires, which were spread around the top rimof the cell, were gathered and also twisted together.

The cell housing consisted of a Pyrex glass test tube with an innerdiameter of about 13-16 mm, depending on the thickness of the rolledelectrode assemblage. Two holes were made on opposite sides of the tube.The electrode assemblage (jelly-roll) prepared as described above wascarefully inserted into the tube, and the anode and cathode leads werefed through the holes. The cell was annealed by heating it slowly in anitrogen atmosphere from 50° C. to 500° C. and holding it for 5 hours.The cell was cooled to room temperature and the holes were sealed withepoxy in a dry box. About 10-20 g of electrolyte was injected into thetube which was then sealed off at the top with an oxygen-acetyleneflame.

Throughout the Examples, this cell type, prepared as described above,will be referred to as “Jelly-roll.”

The present invention is illustrated in more detail by reference to thefollowing Examples, which should not be considered to be limiting thescope of the invention. For brevity and convenience, reference will bemade in these Examples as appropriate to the common materials andprocedures given above. In each Example, the electrodes are referred toherein as the anode and cathode for which are defined, respectively, asthe negative and positive electrodes during cell discharging. Also, allchemical compositions are by mole percent or mole fraction unlessindicated otherwise.

EXAMPLE #1

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. the cathode consists of a saltmixture, xLiCl+(1−x)CaCl₂, where 0.5<x<0.9. The electrodes are supportedon substrates of either carbon or copper; the carbon substrates mayeither stand alone or may be reinforced with a metal such as nickel orplatinum. The electrolyte solvent may consist of any composition withinthe room temperature liquid phase region of the AlCl₃-PCl₅-PCl₃ ternary.For example, the solvent may consist of AlCl₃ and PCl₅ in a 1:1 molarratio, with PCl₃ present at saturation. To impart a high Li⁺ ionicconductivity to the electrolyte, LiAlCl₄ is added at a concentration ofabout 10 m %. The solubility of LiAlCl₄ in the AlCl₃-PCl₅-PCl₃ ternaryis higher than 20 m % over most of the composition range within which asingle liquid phase is formed at room temperature, but generally, amaximum in conductivity as a function of LiAlCl₄ content is reached atless than 10 m %.

FIG. 1 shows the ionic conductivity vs. reciprocal temperature from −20°C. to 120° C. of 2 AlCl₃-PCl₅ with LiCl additions of 0, 10, and 20 m %.The conductivity data shown in FIG. 1 are generally representative ofmolten salt electrolytes within the AlCl₃-PCl₅-PCl₃ ternary. For allthree compositions shown, additions of PCl₃ results in a stabilizedliquid structure and a significant increase in the multiple ionicconductivity, especially for the 2 AlCl₃-PCl₅-0.2 LiCl electrolyte shownin FIG. 1, result in an increase in the conductivity at 25° C. from ˜10³(Ω-cm)⁻¹ to ˜10⁻² (Ω-cm)⁻¹.

The fabrication procedures and performance characteristics of fiverepresentative cells (denoted A through E) using this family of cellcomponent materials are given below.

A. Anode (0.020 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.021 g): 0.9 LiDl-0.1 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart A of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2 LiCl-0.8 CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution depositing technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

A cathode consisting of a 0.9 LiCl-0.1 CaCl₂ salt mixture on acarbon-on-nickel substrate was prepared using a solution depositiontechnique as described above in Part A of Section IV (Electrode CoatingPreparations). The starting solution was prepared by dissolving 11.3 gLiCl and 3.3 g CaCl₂ in 40 ml water. The baking procedure performedbetween immersions and the final baking and annealing steps were thesame as those for the anode of this cell, i.e., as given in Part A(i) ofSection IV (Electrode Coating Preparations). The final weight of thesalt mixture on the cathode substrate was about 0.021 g.

An electrolyte with the nominal composition given above was prepared bydissolving 1.75 g LiAlCl₄ into 38 g AlCl₃-PCl₅-0.3 PCl₃ solvent andheating this mixture to 80° C. until it had homogenized. The startingLiAlCl₄ salt was prepared as described above in Section I (StartingMaterials Preparations). The starting AlCl₃-PCl₅-0.3 PCl₃ solvent wasprepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.5 kΩ so that the charging current was limited 2.0 mA.As charging progressed, this resistor was manually lowered step by stepto keep the charging current at about 2.0 mA until it had reached avalue of about 300 Ω. The charging process was continued thereafteruntil the charging current had dropped to 0.05 mA. The total chargingtime from start to finish was about 4.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was around 60 mA. The cell was dischargedthrough an adjustable resistor which was set to 3.5 kΩ so that theinitial discharging current was 1.0 mA. After about 7.2 hours, the celloutput voltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.02 g): 0.9 LiCl-0.1 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

The fabrication procedures and materials for this cell were otherwisethe same as those of Cell A of this Example.

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.7 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 65 mA. The cell was discharged through anadjustable resistor which was set to 3.5 kΩ so that the initialdischarging current was 1.0 mA. After about 7.5 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.01 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.012 g): 0.9 LiCl-0.1 CaCl₂

Substrate: Carbon-on-Nickel (anode); Copper (cathode)

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 4×10 mm

The cell component materials for this cell were the same as those ofCell A of this Example except that copper foil was substituted forcarbon-on-nickel as the substrate material for the cathode. Theelectrode coatings were prepared using a solution deposition techniqueas described above in Part A of Section IV (Electrode CoatingPreparations). The starting solutions were the same as those of Cell A.Great care had to be taken to insure that the copper foil substrates didnot oxidize during the electrode coating procedures. In this connection,one of the precautions that had to be taken was that all baking stepswere carried out very slowly. For this cell, the baking procedure forthe Cell A electrode salt coatings performed between immersions, i.e.,as given in Part A(i) of Section IV (Electrode Coating Preparations),was modified such that the electrode assemblages were heated in air at arate of 2° C./minute rather than 5° C./minute. Also, the assemblageswere held at 250° C. for five hours rather than at 200° C. for twohours. Afterwards, the assemblages were transferred to a vacuum oven setto 200° C. and held for 10 hours. Once the coatings were built up to thedesired weights, the assemblages were transferred to sealed Pyrex glasstubes and given the same final heat treatment as given in Part A(i) ofSection IV (Electrode Coating Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.4 k Ω so that the charging current was limited 2.0mA. As charging progressed this resistor was manually lowered step bystep to keep the charging current at about 2.0 mA until it had reached avalue of about 300 Ω. The charging process was continued thereafteruntil the charging current had dropped to 0.05 mA. The total chargingtime from start to finish was about 2.5 hours.

The open circuit voltage after charging was 2.7 V, and the maximum shortcut discharging current was 70 mA. The cell was discharged through anadjustable resistor which was set to 2.2 kΩ so that the initialdischarging current was 1.0 mA. After about 4.5 hours, the cell outputvoltage had dropped to 0.5 V.

D. Anode (0.002 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.002 g): 0.8 LiCl-0.2 CaCl₂

Substrate: Carbon

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber substrate-lead assemblages used in thistest cell design are also given therein.

Electrode active material salt mixtures with the nominal compositionsgiven above were deposited on the carbon fiber cluster substrates fromsolution as described above in Part A of Section III (ElectrodeSubstrate Preparations). About 0.002 g of the respective salt mixtureswere deposited on each electrode substrate. For the anode, a solution of8.9 g CaCl₂ and 0.85 g LiCl in 30 ml water was used as the startingsolution. For the cathode, a solution of 2.4 g CaCl₂ and 3.3 g LiCl in30 ml water was used. For both electrodes, the baking procedureperformed between immersions and the final baking and annealing stepswere the same as those described for the electrode type 0.2 LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) of Section IV(Electrode Coating Preparations).

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 38 gAlCl₃-PCl₅-0.3 PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃-PCl₅-0.3 PCl₃ solvent was preparedas described above in Part B(i) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 7.9 kΩ so that the charging current was limited 0.5 mA.As charging progressed, this resistor was manually lowered step by stepto keep the charging current at about 0.5 mA until it had reached avalue of about 1 kΩ. The charging process was continued thereafter untilthe charging current had dropped to 0.01 mA. The total charging timefrom start to finish was about 2.0 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 0.8 mA. The cell was discharged through anadjustable resistor which was set to 12.5 kΩ so that the initialdischarging current was 0.25 mA. After about 3.6 hours, the cell outputvoltage had dropped to 0.5 V.

E. Anode (0.07 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.010 g): 0.8 LiDl-0.2 CaCl₂

Substrate: Carbon-on-platinum

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 2×7 mm

For this cell, a substrate-lead assemblage was constructed for eachelectrode as follows. A 50 mm long Pt wire 0.5 mm in diameter was usedfor both the lead to the external circuit and the reinforcement for theelectrode substrate. A Pt foil rectangle was formed at one end of thewire by flattening it to an area about 7 mm long and 2 mm wide, with theremaining Pt wire centered on one of the 2 mm wide edges. A carbonsubstrate was formed on one side of this Pt rectangle by applying about0.002 g carbon-Teflon-water paste which was prepared according to theprocedure given above in Part C of Section III (Electrode SubstratePreparations) for the carbon-on-nickel substrate, 4×10 mm, Type II(carbon-Teflon paste). The remaining substrate fabrication proceduresare also given therein.

Substrate-lead assemblages fabricated as described above were used forboth electrodes. Electrode active material salt mixtures with thenominal compositions given above were deposited from solution asdescribed above in Part A of Section III (Electrode SubstratePreparations). About 0.02 g salt were deposited on each electrodesubstrate. For the anode, a solution of 8.9 g CaCl₂ and 0.85 g LiCl in10 ml water was used as the starting solution. For the cathode, asolution of 2.4 g CaCl₂ and 3.3 g LiCl in 10 ml water was used. For bothelectrodes, the baking procedure used between immersions and the finalbaking and annealing steps were the same as those used for thepreparation of the electrode type 0.2 LiCl-0.8 CaCl₂, 4×10 mm,carbon-on-nickel, given in Part A(i) of Section IV (Electrode CoatingPreparations).

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 38 gAlCl₃-PCl₅-0.3 PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The AlCl₃-PCl₅-0.3 PCl₃ solvent was prepared asdescribed above in Part B(i) of Section II (Electrolyte Preparations).

The cell was assembled as follows. The two electrode assemblagesprepared as described above were placed into a 100 mm long Pyrex glasstube closed at one end with a 6 mm inner diameter so that the electrodebottom edges were about 10 mm from the bottom of the tube. The Pt wireleads were bent so that the two electrodes would be parallel to oneanother with a gap greater than about 0.5 mm but not exceeding 1 mm. Thepositions of the Pt wire leads and electrodes within the Pyrex glasstube housing were temporarily affixed by clamping the Pt wires to thePyrex tube rim. Glass-to-metal seals were formed between the Pt wiresand Pyrex glass tube rim by heating the glass with an oxygen-acetyleneflame until the glass near the Pt wires became molten. As a final step,about 1.0 g electrolyte was poured into the cell from the top, the cellwas shaken until the electrolyte had settled to the bottom, and the gapbetween the two electrodes was completely filled with electrolyte, andthe top was sealed around the rim with a fitted cover glass and anoxygen-acetylene flame. The amount of electrolyte between the electrodeswas estimated at about 0.03 g.

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 4.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.5 hours.

The open circuit voltage after charging was 3.60 V, and the maximumshort cut discharging current was 75 mA. The cell was discharged throughan adjustable resistor which was set to 6.1 kΩ so that the initialdischarging current was 0.5 mA. After about 7.8 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #2

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of a saltmixture, xLiF+(1−x)CaCl₂, where 0.5<x<0.8. Both electrodes are supportedon carbon substrates reinforced with nickel metal. The electrolytesolvent consist of a 1:1 mixture of AlCl₃ and PCl₅ in which PCl₃ ispresent at saturation; this liquid has the nominal composition,AlCl₃-PCl₅-0.3 PCl₃. To impart a high Li⁺ ionic conductivity to theelectrolyte, LiAlCl₄ is added at a concentration of about 10 m %, andLiF is also added at a concentration of about 1 m %. The fabricationprocedures and performance characteristics of two representative cells(denoted A and B) using this family of cell component materials aregiven below.

A. Anode (0.02 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.035 g): 0.6 LiF-0.4 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃-PCl₃-0.3 PCl₃-0.1 LiAlCl₄-0.01 LiF

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart A of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2 LiCl-0.8 CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

The cathode was prepared by coating a carbon-on-nickel substrate with apaste containing a 0.6 LiF-0.4 CaCl₂ salt mixture using the techniquedescribed above in Part B of Section IV (Electrode CoatingPreparations). The paste was prepared as follows. First, 1.6 g LiF and4.8 g CaCl₂ were combined in a quartz tube and the mixture was heated ina furnace to 700° C. for about 5 hours. After the mixture had cooled toroom temperature, it was transferred to a dry box and crushed with amortar and pestle to a fine powder. A paste was made with this powder byadding 0.1 g of the acetonitrile-01 PPO_(8,000,000) binder; thepreparation of this binder is described in Part B of Section IV(Electrode Coating Preparations). About 0.017-0.018 g of paste wasevenly applied to each side of the substrate which was then squeezedbetween a glass roller and a glass plate. The assemblage was placed intoa large Pyrex glass tube, heated to 180° C. in air, and held for twohours. The tube containing the assemblage was then cooled to roomtemperature, vacuum-sealed, reheated to 600° C., and held for two hours.

An electrolyte with the nominal composition given above was prepared bydissolving 1.75 g LiAlCl₄ and 0.26 g LiF into 38 g AlCl₃-PCl₅-0.3 PCl₃solvent was prepared as described above in Part B(i) of Section II(Electrolyte Preparations). When LiF is added toAlCl₃-PCl₅-PCl₃-PCl₃-LiAlCl₄ electrolytes, they develop a gelatinoustexture after about 10 hours. Therefore, only thoseAlCl₃-PCl₅-PCl₃-LiAlCl₄-LiF electrolytes that are newly-made can be usedduring cell assembly.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.1 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 55 mA. The cell was discharged through anadjustable resistor which was set to 3.05 kΩ so that the initialdischarging current was 1.0 mA. After about 6.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.05 g): 0.5 LiF-0.5 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄-0.01 LiF

Size: 4×10 mm

This cell was prepared from start to finish in exactly the same manneras Cell A of this Example except that for the cathode, the startingmaterials consisted of 1.3 g LiF and 5.6 g CaCl₂ rather than 1.6 g LiFand 4.8 g CaCl₂, and 0.025 g of paste was applied to each side of thesubstrate rather than 0.018 g.

This cell was charged in constant-voltage mode by applying a voltage of4.4 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.4 hours.

The open circuit voltage after charging was 3.50 V, and the maximumshort cut discharging current was 60 mA. The cell was discharged throughan adjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 1.0 mA. After about 6.2 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #3

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of a saltmixture, xLiBr+(1−x)CaCl₂, where 0.5<x<0.9. Both electrodes aresupported on carbon substrates reinforced with nickel metal. Theelectrolyte solvent may consist of any composition within the roomtemperature liquid phase region of the AlCl₃-PCl₅-PCl₃ ternary. Toimpart a high Li⁺ ionic conductivity to the electrolyte, LiAlCl₄ isadded at a concentration of about 10 m %. The fabrication procedures andperformance characteristics of one representative cell (denoted A) usingthis family of cell component materials are given below.

A. Anode (0.02 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.035 g): 0.9 LiBr-0.1 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃-PCl₅-0.3 PCl₃-0.1 LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart A of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2 LiCl-0.8 CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

A cathode consisting of 0.9 LiBr-0.1 CaCl₂ was prepared using a solutiondeposition technique as described above in Part A of Section IV(Electrode Coating Preparations). The total amount of salt deposited onthe cathode substrate was 0.035 g. The starting solution consisted of3.6 g of LiBr and 1.1 g of CaCl₂ dissolved in 50 ml water. The bakingprocedure performed between immersions and the final baking andannealing steps were the same as those used for the anode, i.e., asgiven in Part A(i) of Section IV (Electrode Coating Preparations).

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 38 gAlCl₃-PCl₅-0.3 PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃-PCl₅-0.3 PCl₃ solvent was preparedas described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charge din constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.5 hours.

The open circuit voltage after charging was 3.30 V, and the maximumshort cut discharging current was 40 mA. The cell was discharged throughan adjustable resistor which was set to 2.4 kΩ so that the initialdischarging current was 1.0 mA. After about 6.4 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #4

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)CaCl₂, where 0.5<x<0.95. Both electrodes aresupported on carbon substrates reinforced with either nickel orplatinum. The electrolyte consists of either (1) xLiAlCl₄+(1−x) SOCl₂ or(2) xLiAlCl₄+(1−x)SO₂Cl₂ where for both electrolytes, x may range fromabout 0.02 to 1.5. The fabrication procedures and performancecharacteristics of eight representative cells (denoted A through H)using this family of cell component materials are given below.

A. Anode (0.0025 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.0025 g): 0.9 LiCl-0.1 CaCl₂

Substrate: Carbon-on-platinum

Electrolyte (0.004 g): SOCl₂-0.035 LiAlCl₄

Size: 2×6 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with the following modifications: i) the substrate sizewas 2×6 mm rather than 4×10 mm, ii) the supporting metal was platinumfoil rather than nickel net, ii) the Pt wire lead was spot welded to thecenter of one 2 mm edge and iv) the total amount of carbon-Teflon pastapplied to the nickel net was about 0.05 g rather than 0.01 g.

The anode and cathode coatings were deposited from aqueous solutionsusing the technique described above in Part A of Section IV (ElectrodeCoating Preparations). For this cell, about 0.0025 g of salt wasdeposited on each electrode due to the smaller substrate size. For theanode, a solution of 8.9 g CaCl₂ and 0.85 g LiDl in 30 ml water was usedas the starting solution. For the cathode, a solution of 3.3 g CaCl₂ and11.3 g LiCl in 40 ml water was used. The baking and annealing proceduresused for the fabrication of the electrodes of this cell were the same asthose used for the electrode type 0.2 LiCl-0.8 CaCl₂, 4×10 mm,carbon-on-nickel, given in Part A(i) of Section IV (Electrode CoatingPreparations).

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly). In this case, however,the smaller 2×6 mm electrode assemblages prepared as described abovewere used in place of the usual 4×10 mm assemblages.

This cell was charged by a computer program in constant-voltage mode. Avoltage of about 4.9 V was applied across the cell in series with afixed resistor of 2.1 kΩ and charging was carried out until the chargingcurrent had dropped to about 0.01 mA. The total charging time was about2.0 hours. The open circuit voltage after charging was 3.85 V, and theshort cut discharging current was about 15 mA.

The cell was discharged in constant-current mode at a rate of 0.1 mA forabout 6.0 hours at which point, the cell output voltage had dropped tobelow about 1.0 V.

FIG. 2 shows the charging-discharging curve for this cell. Thedischarging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (0.1 mA)(6.0 h)/(0.00125 g)=240 mAh/g, where 0.00125 gis the amount of working electrode active material on each electrode.The discharging Coulombic capacity for each electrode was determinedfrom the current, time, and weight of the total working active material,i.e., (0.1 mA)(6.0 h/(0.00125 g)=480 mAh/g.

B. Anode (0.048 g): 0.2 LiCl-0.8 CaCl₂

Cathode (0.048 g): 0.9 LiCl-0.1 CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (0.1 g): SO₂Cl₂-0.035 LiAlCl₄

Size: 6×20 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type I (wound carbon fibers)described above in Part A of Section III (Electrode SubstratePreparations) with the following modifications: i) the substrate sizewas 6×20 mm rather than 4×10 mm and ii) the total weight of carbonfibers wound around the nickel net was about 0.025 g rather than 0.01 g.

The electrode coatings were deposited from aqueous solutions using thetechnique described above in Part A of Section IV (Electrode CoatingPreparations). For this cell, about 0.048 g of salt was deposited oneach electrode due to the larger substrate size. The starting solutionfor the anode consisted of 2.52 g LiCl and 26.6 g CaCl₂ in 50 ml water.The starting solution for the cathode consisted of 11.3 g LiCl and 3.3 gCaCl₂ in 40 ml water. For both electrodes, the baking procedureperformed between immersions and the final baking and annealing stepswere the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ in 136 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing the same materials and procedures as those of the Parallel Plate,4×10 mm, design given in Part B of Section V (Cell Assembly), except twoglass paste papers (0.6 mm thick) were inserted between the twoelectrodes. One modification: a Pyrex tube with an inner diameter of 10mm rather than 5 mm was used to house the cell due to the largersubstrate width (i.e., 6 mm). The working electrolyte between twoelectrodes were estimated a about 0.1 g.

This cell was charged by a DC power source in constant-current mode at5.0 mA. The charging voltage started at 1.2 V and increased to 4.0 Vafter about 30 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.8 V, which was a gradualprocess. At that point, a constant current could not be maintained andthe charging process was stopped after about 4.0 hours when the chargingcurrent had dropped to about 0.05 mA. The open circuit voltage aftercharging was 3.85 V, and the maximum short cut discharging current was150 mA.

The cell was discharged through an adjustable resistor with a resistanceof about 1 kΩ for a discharging current value of 3 mA. The dischargingprocess was continued for about 4.2 hours at which point, the celloutput voltage had dropped to 1.0 V with an output current of 1.0 mA. Atthat point, the cell open circuit voltage was measured at about 2.9 Vwith a short cut current of about 25 mA.

FIG. 3a shows the cell voltage and current versus time duringdischarging. FIG. 3b shows the cell output power versus time duringdischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (3 mA)(4.2 h)/(0.024 g+0.024 g)=263mAh/g, where 0.024 g is the amount of working electrode active materialon each electrode. The cathode discharging Coulombic capacity wasdetermined from the current, time, and weight of the total workingcathode active material, i.e., (3 mA)(4.2 h)/(0.024 g)=525 mAh/g.

C. Anode (0.02 g): 0.95LiCl-0.05CaCl₂

 Cathode (0.02 g): 0.95LiCl-0.05CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (in excess) SOCl₂-0.035LiAlCl₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

electrode coatings consisting of a salt mixture of 0.95LiCl-0.05CaCl₂were deposited from aqueous solutions on both electrode substrates usingthe technique described above in Part A of Section IV (Electrode CoatingPreparations). For both electrodes, a starting solution was prepared bydissolving 4.0 g LiCl and 0.55 g CaCl₂ in 30 ml water. The bakingprocedure performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations). The final weight ofdeposited salt on each electrode substrate was 0.02 g.

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.8 V across the cell in series with an adjustable resistor which wasinitially set to 2.8 kΩ so that the charging current was 2.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.5 mA until it had reached a valueof about 500Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 2.4 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 75 mA. The cell was discharged through anadjustable resistor which was set to 3.2 kΩ so that the initialdischarging current was 1.0 mA. After about 5.5 hours, the cell outputvoltage had dropped to 0.5 V.

D. Anode (0.02 g): 0.95LiCl-0.05CaCl₂

 Cathode (0.018 g): 0.95LiCl-0.05CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (exceed): SO₂Cl₂-0.035LiAlCl₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart A of Section III (Electrode Substrate Preparations).

Electrode coatings consisting of a salt mixture of 0.95LiCl-0.05CaCl₂were deposited from aqueous solutions on both electrode substrates usingthe technique described above in part A of Section IV (Electrode CoatingPreparations). For both electrodes, a starting solution was prepared bydissolving 4.0 g LiCl and 0.55 g CaCl₂ in 50 ml water. The bakingprocedure performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations). The final weights ofdeposited salts on the anode and cathode substrates were about 0.02 gand 0.018 g, respectively.

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ in 136 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.8 V across the cell in series with an adjustable resistor which wasinitially set to 2.4 kΩ so that the charging current was 2.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current about 2.5 mA until it had reached a value ofabout 500Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 2.5 hours.

The open circuit voltage after charging was 3.9 V, and the maximum shortcut discharging current was 70 mA. The cell was discharged through anadjustable resistor which was set to 3.3 kΩ so that the initialdischarging current was 1.0 mA. After about 5.5 hours, the cell outputvoltage had dropped to 0.5 V.

E. Anode (1.55 g): 0.5LiCl-0.5CaCl₂

 Cathode (1.56 g): 0.95LiCl-0.05CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SOCl₂-0.05LiAlCl₄

 Size: 40×70 mm

A parallel plate cell with electrode cross sectional areas of about 28cm² was prepared with anode and cathode active materials consisting,respectively, of 0.5LiCl-0.5CaCl₂ and 0.95LiCl-0.05CaCl₂ salt mixtures,each electrode salt mixture supported on carbon-on-nickel substrates.

The carbon-on-nickel substrates were prepared as follows. 70×70 mmsquares of carbon fabric (0.13 g/cm², Zoltek, Inc., Panex®30 fabricPw03) were cleaned by soaking them in concentrated H₂SO₄ for about 10hours and rinsing them thoroughly with water. These carbon fabricsquares were treated further by heating them with a propane flame toaround 1200° C.; this treatment served to drive off impurities and alsosmoothed the surfaces of the carbon fabric by burning off all the tinyfibers sticking out of the surface.

Two nickel net sections were cut for each substrate. The nickel net waswoven from nickel wires with a diameter of 0.17 mm. These sections eachconsisted of a 15×70 mm rectangular section with a thinner rectangular“tail” about 1 mm wide and 100 mm long centered on one of the 15 mmedges. Three nickel wires for use as connections to the externalcircuitry were freed from the net of the tail by removing the crosswires.

The carbon-on-nickel substrates were assembled as follows. The nickelnet rectangles were folded in half along the same axis as that of thenickel wire leads. Two folded nickel net rectangles were positioned atopposite edges of a carbon square by sliding the edges inside until theymade contact with the nickel net rectangle folds. Nickel wires wereremoved from nickel net pieces and were used to permanently affix thenickel net rectangles to the carbon squares. This operation was carriedout at each edge by tightly weaving or sewing two wires through thenickel net-carbon-nickel net layers. Great care was taken to insure thatthe carbon and nickel made excellent contact.

Electrode coatings consisting of salt mixtures with the above nominalcompositions were deposited from aqueous solutions on both electrodesubstrates using the technique described above in Part A of Section IV(Electrode Coating Preparations). For the anode, a starting solution wasprepared by dissolving 4.2 g LiCl and 11.1 g CaCl₂ in 30 ml water. Forthe cathode, a starting solution was prepared by dissolving 4.0 g LiCland 0.55 g CaCl₂ in 50 ml water. The immersion-baking procedure wasrepeated as necessary until the total weights of the LiCl—CaCl₂ saltmixtures on the anode and cathode substrates were about 1.55 g and 1.56g, respectively.

The baking procedure performed after each immersion for this cellconsisted of first heating the coated substrates in air at a rate ofabout 5° C./minute from 50° C. to 250° C., holding them at 250° C. fortwo hours, transferring them to a vacuum oven set at 200° C., andholding them for another two hours. As a final step, the electrodeassemblages were inserted into glass containers, a dried nitrogenatmosphere was introduced, and the glass containers were sealed. Thecontainers were heated slowly from 50° C. to 500° C. and held for about30 minutes.

The electrolyte as prepared by dissolving 8.8 g LiAlCl₄ in 120 g SOCl₂.

The cell was assembled as follows. The two electrodes were placed atopposite ends in a glass container which was 72 mm high, 80 mm wide, and4 mm thick as measured from the inside. The walls of the container wereabout 4 mm thick on all sides. The electrodes were placed in thecontainer such that the pairs of leads on each electrode emerged fromthe top Care was taken to insure that the electrodes were parallel toone another with a gap of 1 mm. This was accomplished by inserting fourglass slides (72×8×1 mm) between the electrodes. These glass slides werearranged in a parallel fashion and distributed uniformly between theedges, exposing three rectangular regions of about 13×70 mm; these threerectangles formed the active electrode surface area of the cell. Thecell was filled with about 70 g electrolyte and was then sealed at thetop with a 12×80 mm glass slide and epoxy which was allowed to set forat least 5 hours. The amount of electrolyte between the electrodes wasestimated at about 60 g.

This cell was charged by a DC power source in constant-current mode at80 mA. The charging voltage started at 1.0 V and increased to 4.0 Vafter about 25 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.9 V. At that point, aconstant current could not be maintained and the charging process wasstopped after about 4.0 hours when the charging current had dropped toabout 1.0 mA. The open circuit voltage after charging was 3.85 V, andthe maximum short cut discharging current was 1.75 A.

The cell was discharged through a light bulb with a resistance about 80Ωfor a discharging current value of 45 mA. The discharging process wascontinued for about 7.2 hours at which point, the cell output voltagehad dropped to 1.8 V with an output current of 25 mA. At the point, thecell open circuit voltage was measured at about 2.8 V with a short cutcurrent of about 90 mA.

FIG. 4a shows the cell voltage and current versus time duringdischarging. FIG. 4b shows the cell output power versus time duringdischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (45 mA)(7.2 h)/(0.775 g+0.780 g)=208mAh/g, where 0.775 g and 0.780 g are the amounts of working electrodeactive material on the anode and cathode, respectively. The cathodedischarging Coulombic capacity was determined from the current, time,and weight of the total working cathode active material, i.e., (45mA)(7.2 h)/(0.780 g)=415 mAh/g.

F. Anode (150 g): 0.5LiCl-0.5CaCl₂

 Cathode (1.52 g): 0.95LiCl-0.05CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SO₂Cl₂-0.04LiAlCl₄

 Size: 40×70 mm

This cell was prepared from start to finish using he same procedures asthose given above for Cell E of this Example except for the electrolytecomposition and the amounts of salts deposited on the electrodesubstrates which were slightly lower than those of Cell E. Theelectrolyte was prepared by dissolving 7.0 g LiAlCl₄ in 136 g SO₂Cl₂.

This cell was charged by a DC power source in constant-current mode at80 mA. The charging voltage started at 1.0 V and increased to 3.8 Vafter about 25 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.9 V. At that point, aconstant current could not be maintained (the charging current startedto drop) and the charging process was stopped for about 4.0 hours whenthe charging current had reduced to 1.0 mA. The open circuit voltageafter charging was 3.8 V, and the maximum short cut discharging currentwas 1.5 A.

The cell was discharged through a light bulb with a resistance of about80Ω for a discharging current value of 45 mA. The discharging processwas continued for about 6.5 hours at which point, the cell outputvoltage had dropped to 1.8 V with an output current of 26 mA. At thatpoint, the cell open circuit voltage was measured at about 2.8 V with ashort cut current of about 100 mA.

G. Anode (1.30 g): 0.5LiCl-0.5CaCl₂

 Cathode (1.42 g): 0.95 LiCl-0.05CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄

 Size: 30×70 mm

For this cell, the carbon-on-nickel substrates were fabricated asfollows. The nickel for the substrate and leads to the external circuitwas cut in one continuous piece from nickel net woven from 0.17 mmdiameter wires; a 30×70 mm section formed the substrate, and 5rectangular “tails” about 2 mm wide were evenly distributed along theentire length of one of the 68 mm edges from one end to the other. Fivenickel wires spaced about 17 mm apart for use as connections to theexternal circuitry were freed from the net by removing the cross wiresfrom the tails.

A paste was made of carbon and polypropylene oxide (PPO) as follows.About 10 g of carbon fibers were cut to 0.5 mm lengths which were thencombined with 0.5 g LiCl and 2 ml water. This mixture was heated in airat a rate of about 5° C./minute from 50° C. to 500° C., held for twohours, and cooled to room temperature. Afterwards, this mixture wascrushed to a fine powder with a mortar and pestle and the LiCl waswashed away with water. The remaining material, which consisted mostlyof carbon, was allowed to dry under ambient conditions and was mixedthoroughly with 0.5 g PPO with a molecular weight of 4,000 (i.e.,PPO₄₀₀₀). About 0.15 g of this paste was evenly applied to each side ofa 28×68 nickel net prepared as described above then smoothed bysqueezing between a glass roller and glass plate. The dimensions of thecarbon-on-nickel substrate after application of this paste were about30×70 mm.

This carbon-on-nickel substrate assemblage was left on the glass plateused to hold it during the application of the carbon-PPO paste. In anargon-filled dry box, the substrate and glass plate were placed in alarge test tube which was plugged up at the open end by stuffing ittightly with glass paste paper. This assemblage was heated at 5°C./minute from 150° C. to 200° C., held for two hours, heated thereafterat 5° C./minute to 500° C., held for one hour, and cooled to roomtemperature. This heat treatment was carried out from start to finish invacuum.

Electrode coatings consisting of salt mixtures with the above nominalcompositions were deposited from aqueous solutions on both electrodesubstrates using the technique described above in Part A of Section IV(Electrode Coating Preparations). For the anode, a starting solution wasprepared by dissolving 4.2 g LiCl and 11.1 g CaCl₂ in 30 ml water. Forthe cathode, a starting solution was prepared by dissolving 4.0 g LiCland 0.55 g CaCl₂ in 50 ml water. The immersion-baking procedure wasrepeated as necessary until the total weights of the LiCl—CaCl₂ saltmixtures on the anode and cathode substrates were about 1.30 g and 1.42g, respectively.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 30×70 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part C of Section V (Cell Assembly).

This cell was charged by a computer program in constant-current mode. Avoltage not exceeding 5.0 V was applied across the cell in series withan adjustable resistor so that the charging current was about 50 mAthroughout the charging process. The open circuit voltage after chargingwas 3.75 V. The cell was discharged through an adjustable resistor sothat the discharging current was 25 mA throughout the dischargingprocess which was carried out until the cell output voltage had droppedto about 1.0 V.

FIG. 5a shows the charging-discharging curve for this cell during thefourth cycle. For this cycle, the total discharging time was about 6.2hours. FIG. 5b shows the middle-cycle-10 charging-discharging curve. Forthis cycle, the total discharging time was about 7.43 hours. Thedischarging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (25 mA)(7.43 h)/(0.65 g+0.71 g)=137 mAh/g, where 0.65 gand 0.71 are the amounts of working electrode active material on theanode and cathode, respectively. The cathode discharging Coulombiccapacity was determined from the current, time, and weight of the totalworking cathode active material, i.e., (25 mA)(7.43 h)/(0.71 g)=262mAh/g. The anode discharging Coulombic capacity was determined from thecurrent, time, and weight of the total working anode active material,i.e., (25 mA)(7.43 h)/(0.65 g)=286 mAh/g. The average dischargingvoltage was about 3.35 V, so the active material average energy densityof this cell was determined at (3.35V)(25 mA)(7.43 h)/(0.65 g+0.71g)=458 mWh/g.

H. Anode (0.162 g): 0.5LiCl-0.5CaCl₂

 Cathode (0.145 g): 0.95LiCl-0.05 CaCl₂

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄

 Size: 15×30 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type III (carbon-PPO paste)described above in Part D of Section III (Electrode SubstratePreparations) with the following modifications: i) the substrate sizewas 15×30 mm rather than 4×10 mm and ii) the total amount of carbon-PPOpaste applied to the nickel net was about 0.25 g rather than 0.02 g.

Electrode active material salt mixtures with the nominal compositionsgiven above were deposited on the carbon-on-nickel substrates fromsolution as described above in Part A of Section III (ElectrodeSubstrate Preparations). For the anode, the starting solution consistedof 4.2 g LiCl and 11.1 g CaCl₂ in 50 ml water. For the cathode, thestarting solution consisted of 8.0 g LiCl and 1.11 g CaCl₂ in 30 mlwater. The amounts of salts deposited on the anode and cathodesubstrates were about 0.162 g and 0.145 g, respectively. For bothelectrodes, the baking procedure performed between immersions and thefinal baking and annealing steps wee the same as those described for theelectrode type 0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given inPart A(i) of Section IV (Electrode Coating Preparations).

The electrolyte for this cell was made by dissolving 6.2 g LiAlCl₄ in136 g SO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing the same materials and procedures as those of the Parallel Plate,4×10 mm, design given in Part B of Section V (Cell Assembly), with onemodification: a Pyrex tube with an inner diameter of 20 mm rather than 5mm was used to house the cell due to the larger substrate width (i.e.,15 mm).

This cell was charged by a computer program in constant-current mode.The charging current was about 100 mA through the charging process. Theopen circuit voltage after charging was 3.8 V. The cell was dischargedthrough an adjustable resistor so that the discharging current was 10 mAthroughout the discharging process which was carried out until the celloutput voltage had dropped to about 0.1 V. The total discharging timewas about 3.7 hours.

FIG. 6 shows the cell voltage versus time during discharging. Thedischarging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (10 mA)(3.7 h)/(0.081 g+0.0725 g)=241 mAh/g, where 0.081g and 0.0725 g are the amounts of working electrode active material onthe anode and cathode, respectively. The cathode discharging Coulombiccapacity was determined from the current, time, and weight of the totalworking cathode active material, i.e., (10 mA)(3.7 h)/0.0725 g)=510mAh/g.

EXAMPLE #5

For this cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)CaCl₂, where 0.5<x<0.95. Both electrodes aresupported on carbon fiber substrates. The electrolyte may consist of oneof

(1−x)SOCl₂ +xLiAlCl₄+0.01LiBF₄   (1)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiBF₄   (2)

(1−x)SOCl₂ +xLiAlCl₄+0.01LiF   (3)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiF   (4)

where for all four electrolytes, x may range from about 0.02 to 1.5 and˜1 m % of either LiF or LiBF₄ is added to the electrolyte to give it agelatinous texture. The fabrication procedures and performancecharacteristics of four representative cells (denoted A through D) usingthis family of cell component materials are given below.

A. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.002 g): 0.9LiCl-0.1CaCl₂

 Substrate: Carbon

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄-0.01LiBF₄

 Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

Electrode active material salt mixtures with the nominal compositionsgiven above were deposited on the carbon fiber cluster substrates fromsolution as described above in Part A of Section III (ElectrodeSubstrate Preparations). About 0.002 g of the respective salt mixtureswere deposited on each electrode substrate. For the anode, a solution of8.9 g CaCl₂ and 0.85 g LiCl in 30 ml water was used as the startingsolution. For the cathode, a solution of 3.3 g CaCl₂ and 11.3 g LiCl in30 ml water was used. For both electrodes, the baking procedureperformed between immersions and the final baking and annealing stepswere the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ and 0.937 gLiBF₄ in 120 g SOCl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.8 V across the cell in series with an adjustable resistor which wasinitially set to 4.4 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.7 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 5.5 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.002 g): 0.9LiCl-0.1CaCl₂

 Substrate: Carbon

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄-0.01LiBF₄

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except that SO₂Cl₂ wassubstituted for SOCl₂ in the electrolyte. The electrolyte for this cellwas prepared by dissolving 6.2 g LiAlCl₄ and 0.937 g LiBF₄ in 136 gSO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.5 hours.

The open circuit voltage after charging was 3.85 V, and the maximumshort cut discharging current was 25 mA. The cell was discharged throughan adjustable resistor which was set to 6.7 kΩ so that the initialdischarging current was 0.5 mA. After about 2.9 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.002 g): 0.9LiCl-0.1CaCl₂

 Substrate: Carbon

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄-0.01LiF

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except that LiF wassubstituted for LiBF₄ in the electrolyte. The electrolyte was preparedby dissolving 6.2 g LiAlCl₄ and 0.259 g LiF in 120 g SOCl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charting current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 1.5 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 5.6 kΩ so that the initialdischarging current was 0.6 mA. After about 2.4 hours, the cell outputvoltage had dropped to 0.5 V.

D. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.002 g): 0.9LiCl-0.1CaCl₂

 Substrate: Carbon

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄-0.01LiF

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except that SO₂Cl₂ wassubstituted for SOCl₂ and LiF was substituted for LiBF₄ in theelectrolyte. The electrolyte was prepared by dissolving 6.2 g LiAlCl₄and 0.259 g LiF in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.6 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 30 mA. The cell was discharged through anadjustable resistor which was set to 6.5 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #6

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)Li₂O, where 0.4<x<0.6 . Both electrodes aresupported on carbon substrates reinforced with nickel metal. Theelectrolyte may consist of either (1) (1−x)SOCl₂ +xLiAlCl₄ or (2)(1−x)SO₂Cl₂ +xLiAlCl₄ where x may range from about 0.02 to 1.5. Thefabrication procedures and performance characteristics of fourrepresentative cells (denoted A through D) using this family of cellcomponent materials are given below.

A. Anode (0.035 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.035 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄

 Size: 4×20 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with the following modification: the substrate size was4×20 mm rather than 4×10 mm. For this substrate, the amount of carbonapplied to the nickel net was about 0.005 g, as for the 4×10 mmsubstrates.

The anode was prepared by depositing a 0.2LiCl-0.8CaCl₂ salt mixturefrom an aqueous solution using the technique described above in Part Aof Section IV (electrode Coating Preparations). The total amount of saltdeposited on the anode substrate was about 0.035 g. A starting solutionconsisting of LiCl and CaCl₂ present at a molar ratio of about 1:4 wasprepared by dissolving 2.52 g LiCl and 26.6 g CaCl₂ in 50 ml water. Thebaking procured performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The cathode coating consisted of a 0.6LiCl-0.4Li₂O salt mixture whichwas prepared as follows. First, 12.6 g LiCl and 9.6 g LiOH were combinedin a quartz tube and the mixture was heated in a furnace to 500° C. forabout 10 hours. After the mixture had cooled to room temperature, it wastransferred to a dry box and the expected loss of water that occurs uponconversion of 2LiOH to Li₂O (i.e., 3.6 g H₂O for 9.6 g LiOH) wasconfirmed by comparing the total weight of the ingredients after the500° C. calcining to their weight prior to that procedure. This mixture,which now consisted of LiCl and Li₂O in a 3:2 molar ratio, was crushedto a fine powder with a mortar and pestle. A paste was made with thispowder by adding 0.1 g of the acetonitrile-01PPO_(8,000,000) binder, thepreparation of this binder is described in Part B of Section IV(Electrode Coating Preparations). About 0.017-0.018 g of this paste wasevenly applied to each side of the substrate which was then squeezedbetween a glass roller and a glass plate. The cathode assemblage wasplaced into a Pyrex glass tube, heated to 150° C. in air, and held fortwo hours. The tube containing the assemblage was then cooled to roomtemperature, vacuum-sealed, reheated to 600° C., and held for two hours.

The electrolyte for this cell was prepared by dissolving 6.2 g LiAlCl₄in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Pate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly). In this case, however,the longer 4×20 mm electrode assemblages prepared as described abovewere used in place of the usual 4×10 mm assemblages.

This cell was charged by a DC power source in constant-current mode at5.0 mA. The charging voltage started at 1.2 V and increased to 4.0 Vafter about 20 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.8 V, which was a gradualprocess. At that point, a constant current could not be maintained andthe charging process was stopped after about 4.2 hours when the chargingcurrent had dropped to about 0.05 mA. The open circuit voltage aftercharging was 3.9 V, and the maximum short cut discharging current was 65mA.

The cell was discharged through an adjustable resistor with a resistanceof about 3.6 kΩ for a discharging current value of 1.0 mA. Thedischarging process was continued for about 9.4 hours at which point,the cell output voltage had dropped to 0.5 V with an output current of0.2 mA. At that point, the cell open circuit voltage was measured atabout 2.9 V with a short cut current of about 30 mA.

FIG. 7a shows the cell voltage versus time during discharging for thiscell. FIG. 7b shows the cell output power versus time duringdischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (1 mA)(9.4 h)/(0.0175 g+0.0175 g)=269mAh/g, where 0.0175 g is the amount of working electrode active materialon each electrode. The discharging Coulombic capacity for each electrodewas determined from the current, time, and weight of the total workingcathode active material, i.e., (1 mA)(9.4 h)/(0.0175 g)=537 mAh/g. Theaverage discharging voltage was about 3.35 V, so the active materialaverage energy density of this cell was determined at (3.35V)(1 mA)(9.4h)/(0.0175 g+0.0175 g)=900 mWh/g.

B. Anode (0.025 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.025 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare the same as those given in Part A(i) of Section IV (ElectrodeCoating Preparations) with one modification: the amount of saltdeposited on the substrate was about 0.025 g rather than 0.02 g.

The cathode was prepared from start to finish using the same proceduresand materials as those of Cell A of this Example except that the totalamount of salt applied to the substrate was about 0.025 g rather than0.035 g due to the difference in substrate sizes between Cells A and B.

The electrolyte for this cell was prepared by dissolving 6.2 g LiAlCl₄in 136 g SO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.5 kΩ so that the charging current was 2.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.5 mA until it had reached a valueof about 500Ω. the charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.2 hours.

The open circuit voltage after charging was 3.9 V, and the maximum shortcut discharging current was 70 mA. The cell was discharged through anadjustable resistor which was varied from one cycle to the next so thatthe discharging behavior for this cell could be measured as a functionof discharging current. Discharging was continued for each cycle untilthe cell output voltage had dropped to 0.5 V.

FIGS. 8a and b show the cell voltage versus time during discharging fordischarging currents of 5 mA and 2 mA, respectively. For FIG. 8a, thedischarging time is 1.35 hours and the cell Coulombic capacity iscalculated at (5 mA)(1.35 h)/(0.0125 g+0.0125 g)=270 mAh/b, where 0.0125g is the amount of electrode active material on each electrode. For FIG.8b, the discharging time is 3.45 hours and the cell Coulombic capacityis calculated at (2 mA)(3.45 h)/(0.0125 g+0.0125 g)=276 mAh/g. Fromthese results, it can be seen that the lower discharge rate results in asomewhat higher Coulombic capacity for this cell.

C. Anode (0.02 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.02 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

The cathode was prepared from start to finish using the same proceduresand materials as those of Cell A of this Example except that the totalamount of salt applied to the substrate was about 0.02 g rather than0.035 g due to the difference in substrate sizes.

The electrolyte for this cell was prepared by dissolving 6.2 g LiAlCl₄in120 g SO₂Cl₂.

The charging procedure was the same as that of Cell B of this Example.FIG. 8c shows the cell voltage versus time during discharging. Duringdischarging, the current was 2.0 mA and the total discharging time wasabout 2.7 hours. The Coulombic capacity of the cell is calculated at (2mA)(2.7 h)/(0.01 g+0.01 g)=270 mAh/g.

D. Anode (0.35 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.352 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon-on-nickel

 Electrolyte (10 g): SOCl₂-0.035LiAlCl₄

 Size: 30×70 m

The cell component materials are the same as those of Cells A and C ofthis Example; for this cell, a larger test cell design with an electrodecross sectional area of 21 cm² was employed.

The carbon-on-nickel substrates were prepared from start to finish usingthe same materials and procedures as those of the carbon-on-nickelsubstrate, 4×10 mm, Type II (carbon-Teflon paste) described above inPart C of Section III (Electrode Substrate Preparations) with thefollowing modifications: i) the substrate size was 30×70 mm rather than4×10 mm, ii) the total amount of carbon-Teflon paste applied to thenickel net was about 0.8 g rather than 0.02 g and iii) the subsequentheat treatment was different from that of the 4×10 mm substrates. Thesubstrate preparation procedures with these modifications are given inmore detail below.

First, the nickel for the substrate and lead to the external circuit wascut in one continuous piece from nickel net; a 30×70 mm section formedthe substrate, and a thinner rectangular “tail” 2 mm wide was centeredon one of the 30 mm edges. Four nickel wires for use as connections tothe external circuitry were freed from the net by removing the crosswires. About 0.4 g carbon-Teflon-water paste was applied evenly to eachside of the nickel net, and the paste was smoothed by squeezing betweena glass roller and a glass plate, making certain that each side wasthoroughly covered so that the nickel metal would never be exposed tothe electrolyte during cell operation. This carbon-on-nickel substrateassemblage was vacuum heated at 200° C. for 10 hours, cooled to roomtemperature, placed in a vacuum-sealed Pyrex glass tube, and given afinal heat treatment at 600° C. for two hours. The total amount ofcarbon on the substrate once all the preparations were complete wasabout 0.7 g.

The anode was prepared by depositing a 0.2LiCl-0.8CaCl₂ salt mixturefrom an aqueous solution using the technique described above in Part Aof Section IV (Electrode Coating Preparations). The total amount of saltdeposited on the anode substrate was about 0.35 g. A starting solutionconsisting of LiCl and CaCl₂ present at a molar ratio of about 1:4 wasprepared by dissolving 2.52 g LiCl and 26.6 g CaCl₂ in 50 ml water. Thebaking procedure performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The cathode was prepared by applying a paste containing the saltmixture, 0.6LiCl-0.4Li₂O, prepared as described for Cell A of thisExample. About 0.176 g of paste was evenly applied to each side of thesubstrate which was then squeezed between a glass roller and a glassplate. This cathode assemblage was placed in a large glass test tubewith the open end stuffed with glass paste paper and transferred to avacuum furnace, wherein it was heated from 50° C. to 200° C. at a rateof 5° C./minute then held for about 5 hours. Then, a nitrogen atmospherewas introduced into the furnace, and the assemblage was heated from 200°C. to 450° C. and held thereafter for 5 hours.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 30×70 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part C of Section V (Cell Assembly).

This cell was charged and discharged by a computer program inconstant-current mode. The charging voltage upper limit was set to 5.0V. FIGS. 9a and b show the cell voltage versus time during dischargingduring the second and third cycles. For both cycles, the cell wasdischarged at a rate of 40 mA, and the total discharging time was about2.5 hours. The discharging Coulombic capacity of the cell was determinedfrom the current, time, and weight of the total working electrode activematerial, i.e., (40 mA)(2.5 h)/(0.175 g+0.176 g)=285 mAh/g, where 0.175g and 0.176 g are the amounts of working electrode active material onthe anode and cathode, respectively, The cathode discharging Coulombiccapacity was determined from the current, time, and weight of the totalworking cathode active material, i.e., (40 mA)(2.5 h)/(0.176 g)=568mAh/g.

EXAMPLE #7

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)Li₂O, where 0.4<x<0.6. Both electrodes are supportedon carbon fiber cluster substrates. The electrolyte may consist of oneof

(1−x)SOCl₂ +xLiAlCl₄+0.01LiBF₄   (1)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiBF₄   (2)

(1−x)SOCl₂ +xLiAlCl₄+0.01LiF   (3)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiF   (4)

where for all four electrolytes, x may range from about 0.02 to 1.5 and˜1m % of either LiF or LiBF₄ is added to the electrolyte to give it agelatinous texture. The fabrication procedures and performancecharacteristics of four representative cells (denoted A through D) usingthis family of cell component materials are given below.

A. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.0013 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄-0.01LiBF₄

 Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

For the anode, about 0.002 g of a salt mixture with the above nominalcomposition was deposited on a carbon fiber cluster substrate using thetechnique described above in Part A of Section IV (Electrode CoatingPreparations). The starting solution consisted of 8.9 g CaCl₂ and 0.85 gLiCl in 10 ml water. The baking procedure performed between immersionsand the final baking and annealing steps were the same as thosedescribed for the electrode type 0.2LiCl-0.8CaCl₂, 4×10 mm,carbon-on-nickel, given in Part A(i) of Section IV (Electrode CoatingPreparations).

For the cathode, about 0.0013 g of a paste consisting of a salt mixturewith the above nominal composition was applied to a carbon fiber clustersubstrate. This paste was prepared as follows. First, 12.6 g LiCl and9.6 g LiOH were combined in a quartz tube and the mixture was heated ina furnace to 500° C. for about 10 hours. After the mixture had cooled toroom temperature, it was transferred to a dry box and the expected lossof water that occurs upon conversion of 2LiOH to Li₂O (i.e., 3.6 g H₂Ofor 9.6 g LiOH) was confirmed by comparing the total weight of theingredients after the 500° C. calcining to their weight prior to thatprocedure. This mixture, which now consisted of LiCl and Li₂O in a 3:2molar ratio, was crushed to a fine powder with a mortar and pestle. Apaste was made with this powder by adding 0.1 g of theacetonitrile-01PPO_(8,000,000) binder. After the paste was applied tothe substrate, the cathode assemblage was placed into a Pyrex glasstube, heated to 150° C. in air, and held for two hours. The tubecontaining the assemblage was then cooled to room temperature,vacuum-sealed, reheated to 600° C., and held for two hours.

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ and 0.937 gLiBF₄ in 120 g SOCl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.5 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 5.6 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.0013 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄-0.01LiBF₄

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same procedures asthose given in Cell A of this Example except that for the electrolyte,SO₂Cl₂ was substituted for SOCl₂. The electrolyte was prepared bydissolving 6.2 g LiAlCl₄ and 0.937 g LiBF₄ in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.6 hours.

The open circuit voltage after charging was 3.85 V, and the maximumshort cut discharging current was 28 mA. The cell was discharged throughan adjustable resistor which was set to 6.7 kΩ so that the initialdischarging current was 0.5 mA. After about 3.2 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.0015 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄-0.01LiF

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same procedures asthose given in Cell A of this Example except that for the electrolyte,LiF was substituted for LiBF₄. The electrolyte was prepared bydissolving 6.2 g LiAlCl₄and 0.259 g LiF in 120 g SOCl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.4 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.5 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 5.4 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

D. Anode (0.002 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.0013 g): 0.6LiCl-0.4Li₂O

 Substrate: Carbon

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄-0.01LiF

 Size: 1.2×10 mm

This cell was prepared from start to finish using the same procedures asthose given in Cell A of this Example except that for the electrolyte,SO₂Cl₂ was substituted for SOCl₂ and LiF was substituted for LiBF₄. Theelectrolyte was prepared by dissolving 6.2 g LiAlCl₄ and 0.259 g LiF in136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 4.5 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.6 hours.

The open circuit voltage after charging was 3.85 V, and the maximumshort cut discharging current was 35 mA. The cell was discharged throughan adjustable resistor which was set to 5.5 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #8

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)[yLi₂O+(1−y)Li₂CO₃], where 0.4<x<0.6 and 0.6y<0.9.Both electrodes are supported on carbon substrates reinforced withnickel metal. The electrolyte may consist of either (1) (1−x)SOCl₂+xLiAlCl₄ or (2) (1−x)SO₂Cl₂ +xLiAlCl₄ were x may range from about 0.02to 1.5 The fabrication procedures and performance characteristics offour representative cells (denoted A through D) using this family ofcell component materials are given below.

A. Anode (0.04 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.045 g): 0.4LiCl-0.48Li₂-0.12Li₂CO₃ (i.e.,0.4LiCl-0.6[0.8Li₂O-0.2Li₂CO₃])

 Substrate: Carbon-on-nickel

 Electrolyte (0.1 g): SOCl₂-0.035LiAlCl₄

 Size: 8×15 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type III (carbon-PPO paste)described above in Part D of Section III (Electrode SubstratePreparations) with the following modifications: i) the substrate sizewas 8×15 mm rather than 4×10 mm and ii) the total amount of carbon-PPOpaste applied to the nickel net was about 0.06 g rather than 0.02 g.

An anode consisting of a 0.2LiCl-0.8CaCl₂ salt mixture on acarbon-on-nickel substrate was prepared by depositing a salt mixturewith this nominal composition from an aqueous solution using thetechnique described above in Part A of Section IV (Electrode CoatingPreparations). The total amount of slat applied to the substrate wasabout 0.04 g. The starting solution consisted of 2.52 g LiCl and 26.6 gCaCl₂ dissolved in 50 ml water. The baking procedure performed betweenimmersions and the final baking and annealing steps were the same asthose described for the electrode type 0.2LiCl-0.8CaCl₂, 4×10 mm,carbon-on nickel, given in Part A(i) of Section IV (Electrode CoatingPreparations).

The cathode for this cell was prepared from start to finish using thesame materials and procedures as those given above in Part B(ii) ofSection IV (Electrode Coating Preparations) for the electrode type0.4LiCl-0.48Li₂O-0.12Li₂CO₃, 4×10 mm, carbon-on-nickel, but with thefollowing modifications: i) the substrate size was 8×15 mm rather than4×10 mm and ii) the total amount of salt applied to the substrate wasabout 0.045 g due to the larger substrate size.

The electrolyte for this cell was prepared by dissolving 6.2 g LiAlCl₄in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialusing the same materials and procedures as those of the Parallel Plate,4×10 mm, design given in Part B of Section V (Cell Assembly), except twoglass paste papers were inserted between the two electrodes. Onemodification: a Pyrex tube with an inner diameter of 10 mm rather than 5mm was used to house the cell due to the larger substrate width (i.e., 8mm).

This cell was charged in constant-current mode at 20 mA for 30 minutes.The open circuit voltage after charging was 3.8 V. The cell wasdischarged in constant-current mode at a rate of 5 mA. The totaldischarging time was about 1.83 hours.

FIG. 10 shows the cell voltage versus time during discharging. Thedischarging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (5 mA)(1.83 h)/(0.02 g+0.0225 g)=215 mAh/g, where 0.02 gand 0.0225 g are the amounts of working electrode active material on theanode and cathode, respectively. The cathode discharging Coulombiccapacity was determined from the current, time, and weight of the totalworking cathode active material, i.e., (5 mA)(1.83 h)/(0.0225 g)=407mAh/g.

B. Anode (0.03 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.028 g): 0.4LiCl-0.48Li₂O-0.12Li₂CO₃

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SO₂Cl₂-0.035LiAlCl₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type III(carbon-PPO paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart D of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare the same as those given in Part A(i) of Section IV (ElectrodeCoating Preparations) with one modification: the amount of saltdeposited on the substrate was about 0.03 g rather than 0.02 g.

An electrode of the type, 0.4LiCl-0.48Li₂O-0.12Li₂CO₃, 4×10 mm,carbon-on-nickel, prepared by applying the coating as a paste,constituted the cathode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartB(ii) of Section IV (Electrode Coating Preparations). The total amountof salt applied to the substrate was about 0.028 g.

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ in 136 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged by a DC power source in constant-current mode at5.0 mA. The charging voltage started at 1.0 V and increased to 4.0 Vafter about 15 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.9 V, which was a gradualprocess. At that point, a constant current could not be maintained andthe charging process was stopped after about 2.5 hours when the chargingcurrent had dropped to about 0.5 mA. The open circuit voltage aftercharging was 3.85 V, and the maximum short cut discharging current was30 mA.

The cell was discharged through an adjustable resistor with a resistanceof about 2.9 kΩ for a discharging current value of 1.5 mA. Thedischarging process was continued for about 6.2 hours at which point,the cell output voltage had dropped to 1.0 V with an output current of0.5 mA. At that point, the cell open circuit voltage was measured atabout 2.8 V with a short cut current of about 5 mA.

FIG. 11a shows the cell voltage versus time during discharging for thiscell. FIG. 11b shows the cell output power versus time duringdischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (1.5 mA)(6.2 h)/(0.015 g+0.014 g)=321mAh/g, where 0.015 g and 0.014 g are the amounts of working electrodeactive material on the anode and cathode, respectively. The cathodedischarging Coulombic capacity was determined from the current, time,and weight of the total working cathode active material, i.e., (1.5mA)(6.2 h)/(0.014 g)=664 mAh/g.

C. Anode (0.2 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.173 g): 0.4LiCl-0.48Li₂O-0.12Li₂CO₃

 Substrate: Carbon-on-nickel

 Electrolyte (14 g): SOCl₂-0.035LiAlCl₄

 Size: 50×70 mm

This cell has the same cell component materials as Cell A of thisExample, but the test cell used herein is larger and employs ajelly-roll design rather than a parallel plate or carbon fiber clustersubstrate configuration. For this cell, carbon-on-nickel substrates,50×70 mm, Type IV (carbon-acetonitrile-PPO slurry) were used for bothelectrodes. The materials and preparation procedures for this substratedesign are described in Part E of Section III (Electrode SubstratePreparations).

An anode consisting of 0.2LiCl-0.8CaCl₂ was prepared using a solutiondeposition technique as described above in Part A of Section IV(Electrode Coating Preparations). The starting solution consisted of2.52 g LiCl and 26.6 g CaCl₂ dissolved in 50 ml water. The total amountof salt deposited on the cathode substrate was about 0.2 g. The bakingprocedure performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The cathode for this cell was prepared from start to finish using thesame materials and procedures as those given above in Part B(ii) ofSection IV (Electrode Coating Preparations) for the electrode type0.4LiCl-0.48Li₂O-0.12Li₂CO₃, 4×10 mm, carbon-on-nickel, but with thefollowing modifications: i) the substrate size was 50×70 mm rather than4×10 mm and ii) the total amount of salt applied to the substrate wasabout 0.173 g due to the larger substrate size.

A cell was assembled from the above-described cell component materialsusing the Jelly-roll test cell design. The materials and preparationprocedures for this test cell design are described in Part D of SectionV (Cell Assembly).

This cell was repeatedly charged and discharged for over 550 hours usinga constant current charging and discharging computer program. Thecharging and discharging currents were set at 120 mA and 25 mA,respectively. The open circuit voltage after charging was 3.2 V, and thecell exhibited a cathode discharging Coulombic capacity of about 370-490mAh/g throughout.

FIGS. 12a-c show the cell output voltage versus time during dischargingfor the first, 50th, and 100th cycles. For all cycles, discharging wascarried out at 25 mA. For the first cycle, the total discharging timewas 3.39 hours and the discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (25 mA)(3.39 h)/(0.2 g+0.173 g)=227mAh/g, were 0.2 g and 0.173 g are the amounts of working electrodeactive material on the anode and cathode, respectively. The cathodedischarging Coulombic capacity was determined from the current, time,and weight of the total working cathode active material, i.e., (25mA)(3.39 h)/(0.173 g)=490 mAh/g. For this jelly roll design, the totalworking electrode active material included the material on both sides ofthe substrates.

For the 50th cycle, the total discharging time was 3.38 hours and thetotal cell and cathode Coulombic capacities, respectively, weresimilarly determined at 227 mAh/g and 488 mAh/g.

For the 100th cycle, the total discharging time was 2.62 hours and thetotal cell and cathode Coulombic capacities, respectively, weresimilarly determined at 176 mAh/g and 379 mAh/g.

D. Anode (0.2 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.120 g): 0.4LiCl-0.48Li₂O-0.12Li₂CO₃

 Substrate: Carbon-on-nickel

 Electrolyte (13 g): SOCl₂-0.035LiAlCl₄

 Size: 50×70 mm

This cell has the same cell component materials as those Cell A and C ofthis Example and employs a jelly-roll design. For this cell, carbon onnickel substrates, 50×70 mm, Type V (carbon-acetonitrile-PPO slurry)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part F of Section III(Electrode Substrate Preparations). The substrate design employed hereindiffers from most of the other designs in that it consists of carbonfabric.

Both electrodes for this cell were prepared as described above for CellC of this example due to the similar substrate size of both cells.

A cell was assembled from the above-described cell component materialsusing the Jelly-roll test cell design. The materials and preparationprocedures for this test cell design are described in Part D of sectionV (Cell Assembly).

This cell was repeatedly charged and discharged using a constant currentcharging and discharging computer program. The charging and dischargingcurrents were set at 60 mA and 25 mA, respectively. The open circuitvoltage after charging was 3.2 V, and the cell exhibited a cathodedischarging Coulombic capacity of about 450 mAh/g throughout. These cellattributes are very similar to those of Cell C of this Example.

EXAMPLE #9

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of a saltmixture, xLiCl+(1−x)[yLi₂O+(1−y)Li₂CO₃], where 0.4<x<0.6 and 0.6<y<0.9.Both electrodes are supported on carbon substrates reinforced withnickel metal. The electrolyte may consist of one of

(1−x)SOCl₂ +xLiAlCl₄+0.01LiBF₄   (1)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiBF₄   (2)

(1−x)SOCl₂ +xLiAlCl₄+0.01LiF   (3)

(1−x)SO₂Cl₂ +xLiAlCl₄+0.01LiF   (4)

where for all four electrolytes, x may range from about 0.02 to 1.5 and˜1 m % of either LiF or LiBF₄ is added to the electrolyte to give it agelatinous texture. The fabrication procedures and performancecharacteristics of four representative cells (denoted A through D) usingthis family of cell component materials are given below.

A. Anode (0.02 g): 0.2LiCl-0.8CaCl₂

 Cathode (0.012 g): 0.4LiCl-0.48Li₂O-0.12Li₂CO₃

 Substrate: Carbon-on-nickel

 Electrolyte (in excess): SOCl₂-0.035LiAlCl₄-0.01LiBF₄

 Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type III(carbon-PPO paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart D of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl-0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

An electrode of the type, 0.4LiCl—0.48Li₂O—0.12Li₂CO₃, 4×10 mm,carbon-on-nickel, prepared by applying the coating as a paste,constituted the cathode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartB(ii) of Section IV (Electrode Coating Preparations). The total amountof salt applied to the substrate was about 0.012 g.

The electrolyte was prepared by dissolving 6.2 g LiAlCl₄ and 0.937 gLiBF₄ in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 75 mA. The cell was discharged through anadjustable resistor which was set to 3.2 kΩ so that the initialdischarging current was 1.0 mA. After about 6.0 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): 0.4LiCl—0.48Li₂O—0.12Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.035LiAlCl₄—0.01LiBF₄

Size:4×10 mm

This cell was fabricated from start to finish using the same materialsand procedures as those of Cell A of this Example except that for theelectrolyte, SO₂Cl₂ was substituted for SOCl₂. The electrolyte wasprepared by dissolving 6.2 g LiAlCl₄ and 0.937 g LiBF₄ in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.5 mA until it had reached a valueof about 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.9 V, and the maximum shortcut discharging current was 88 mA. The cell was discharged through anadjustable resistor which was set to 3.3 kΩ so that the initialdischarging current was 1.0 mA. After about 8.5 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): 0.4LiCl—0.48Li₂O—0.12Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.035LiAlCl₄—0.01LiF

Size: 4×10 mm

This cell was fabricated from start to finish using the same proceduresas those of Cell A of this Example except that for the electrolyte, LiFwas substituted for LiBF₄. The electrolyte was prepared by dissolving6.2 g LiAlCl₄ and 0.259 g LiF in 120 g SOCl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.8 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.0 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 85 mA. The cell was discharged through anadjustable resistor which was set to 3.2 kΩ so that the initialdischarging current was 1.0 mA. After about 7.8 hours, the cell outputvoltage had dropped to 0.5 V.

D. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): 0.4LiCl—0.48Li₂O—0.12Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.035LiAlCl₄—0.01LiF

Size: 4×10 mm

This cell was fabricated from start to finish using the same proceduresas those of Cell A of this Example except that for the electrolyte,SO₂Cl₂ was substituted for SOCl₂ and LiF was substituted for LiBF₄. Theelectrolyte was prepared by dissolving 6.2 g LiAlCl₄ and 0.259 g LiF in136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.8 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.3 hours.

The open circuit voltage after charging was 3.5 V, and the maximum shortcut discharging current was 90 mA. The cell was discharged through anadjustable resistor which was set to 2.9 kΩ so that the initialdischarging current was 1.0 mA. After about 8.5 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #10

For the cells of this Example, the anode consists of carbon. The cathodeconsists of Li₂CoO₂. Both electrodes substrates consist of carbonreinforced by platinum metal. The electrolyte may consist of either

(1−x)SO₂Cl₂+xLiAlCl₄+0.01LiF   (1)

AlCl₃+PCl₅+POCl₃+0.1LiAlCl₄+0.01LiF   (2)

where, for both electrolytes, x may range from about 0.02 to 1.5 andabout 1 m % LiF is added to impart a gelatinous texture. The fabricationprocedures and performance characteristics of two representative cells(denoted A and B) using this family of cell component materials aregiven below.

A. Anode (0.025 g): Carbon

Cathode (0.022 g): Li₂CoO₂

Substrate: Carbon-on-platinum

Electrolyte (in excess): SO₂Cl₂—0.4LiAlCl₄—0.01LiF

Size: 4×10 mm

For this cell, carbon-on-platinum substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart B of Section III (Electrode Substrate Preparations).

For the anode substrate, the total weight of wound carbon fibers on theplatinum support was about 0.01 g. This carbon constituted the activeanode material.

The cathode was prepared as follows. The Li₂CoO₂ was prepared bycombining 14.8 g Li₂CO₃ and 33.17 CoCl₂ in a quartz test tube, heatingthe mixture to 850° C. in air, and holding it for 10 hours. During thisheat treatment, the color of the powder mixture (now Li₂CoO₂) changedfrom blue to black. The Li₂CoO₂ was cooled to room temperature andcrushed to a powder with a mortar and pestle. A paste was made from theLi₂CoO₂ powder by combining it with about 0.1 g of theacetonitrile-01PPO_(8,000,000) binder; the preparation of this binder isdescribed in Part B of Section IV (Electrode Coating Preparations).About 0.011 g of the paste was evenly applied to each side of acarbon-on-platinum substrate. The paste was smoothed by squeezing itbetween a glass roller and a glass plate. The cathode assemblage wasplaced into Pyrex glass tube, heated to 150° C. in air, and held for twohours. The tube containing the assemblage was then cooled to roomtemperature, vacuum-sealed, reheated to 600° C., and held for two hours.

The electrolyte was prepared by dissolving 7.0 g LiAlCl₄ and 0.259 g LiFin 136 g SO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of5.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.3 hours.

The open circuit voltage after charging was 4.0 V, and the maximum shortcut discharging current was 75 mA. The cell was discharged through anadjustable resistor which was set to 3.2 kΩ so that the initialdischarging current was 1.0 mA. After about 8.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.025 g): Carbon

Cathode (0.022 g): Li₂CoO₂

Substrate: Carbon-on-platinum

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄ —0.01LiF

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

An electrolyte with the nominal composition given above was prepared bydissolving 1.75 g LiAlCl₄ and 0.26 g LiF into 39 g AlCl₃—PCl₅—0.3POCl₃solvent and heating this mixture to 80° C. until it had homogenized. Thestarting AlCl₃—PCl₅—0.3POCl₃ solvent was prepared as described above inPart B(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.4 hours.

The open circuit voltage after charging was 3.65 V, and the maximumshort cut discharging current was 75 mA. The cell was discharged throughan adjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 1.0 mA. After about 8.0 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #11

For the cells of this Example, the anode consists of carbon. The cathodeconsists of Li₂MnO₂. Both electrodes substrates consist of carbonreinforced by platinum metal. The electrolyte may consist of either

(1−x)SO₂Cl₂+xLiAlCl₄+0.01LiF  (1)

AlCl₃+PCl₅+POCl₃+0.1LiAlCl₄+0.01LiF  (2)

where, for both electrolytes, x may range from about 0.02 to 1.5 andabout 1 m % LiF is added to impart a gelatinous texture. The fabricationprocedures and performance characteristics of two representative cells(denoted A and B) using this family of cell component materials aregiven below.

A. Anode (0.025 g): Carbon

Cathode (0.022 g): Li₂MnO₂

Substrate: Carbon-on-platinum

Electrolyte (in excess): SO₂Cl₂—0.4LiAlCl₄—0.01LiF

Size: 4×10 mm

For this cell, carbon-on-platinum substrates, 4×10 mm, Type I (woundcarbon fibers) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart B of Section III (Electrode Substrate Preparations).

For the anode substrate, the total weight of wound carbon fibers on theplatinum support was about 0.01 g. This carbon constituted the activeanode material.

The cathode was prepared as follows. The Li₂MnO₂ was prepared bycombining 7.4 g Li₂CO₃ and 12.5 g MnCl₂ in a quartz test tube, heatingthe mixture to 900° C. in air, and holding it for 10 hours. During thisheat treatment, the color of the powder mixture (now Li₂MnO₂) changedfrom pink to black. The Li₂MnO₂ was cooled to room temperature andcrushed to a powder with a mortar and pestle. A paste was made from theLi₂MnO₂ powder by combining it with about 0.1 g of theacetonitrile-01PPO_(8,000,000) binder; the preparation of this binder isdescribed in Part B of Section IV (Electrode Coating Preparations).About 0.011 g of the paste was evenly applied to each side of acarbon-on-platinum substrate. The paste was smoothed by squeezing itbetween a glass roller and a glass plate. The cathode assemblage wasplaced into Pyrex glass tube, heated to 150° C. in air, and held for twohours. The tube containing the assemblage was then cooled to roomtemperature, vacuum-sealed, reheated to 600° C., and held for two hours.

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.0 hours.

The open circuit voltage after charging was 3.85 V, and the maximumshort cut discharging current was 65 mA. The cell was discharged throughan adjustable resistor which was set to 3.25 kΩ so that the initialdischarging current was 1.0 mA. After about 7.8 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.025 g): Carbon

Cathode (0.022 g): Li₂MnO₂

Substrate: Carbon-on-platinum

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄—0.01LiF

Size: 4×10 mm

This cell was fabricated from start to finish using the same materialsand procedures as those of Cell A of this Example except for theelectrolyte which was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ and 0.26 g LiFinto 39 g AlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C.until it had homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent wasprepared as described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 4.1 hours.

The open circuit voltage after charging was 3.9 V, and the maximum shortcut discharging current was 60 mA. The cell was discharged through anadjustable resistor which was set to 3.3 kΩ so that the initialdischarging current was 1.0 mA. After about 8.0 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #12

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.4. The cathode consists of a saltmixture, xLiOCN+(1−x)AlCl₃, where 0.8<x<0.95. Both electrodes aresupported on carbon fiber cluster substrates. The electrolyte mayconsist of either (1) (1−x)SO₂Cl₂+xLiAlCl₄, where 0.02<x<1.5, or (2)AlCl₃+PCl₅+0.3POCl₃+0.1LiAlCl₄. The fabrication procedures andperformance characteristics of two representative cells (denoted A andB) using this family of cell component materials are given below.

A. Anode (0.005 g): 0.2LiCl—0.8CaCl₂

Cathode (0.005 g): 0.9LiOCN—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

Electrode active material salt mixtures with nominal compositions asgiven above were deposited on the carbon fiber cluster substrates fromaqueous solutions using the technique described above in Part A ofSection IV (Electrode Coating Preparations). About 0.005 g of salt weredeposited on each electrode substrate. For the anode, a solution of 8.9g CaCl₂ and 0.85 g LiCl in 10 ml water was used as the startingsolution. For the cathode, a solution of 4.4 g LiOCN and 1.3 g AlCl₃ in20 ml water was used. For both electrodes, the baking procedureperformed between immersions and the final baking and annealing stepswere the same as those described for the electrode type0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

The electrolyte for this cell was prepared by dissolving 7.0 g LiAlCl₄in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 2.1 hours.

The open circuit voltage after charging was 3.85 V, and the maximumshort cut discharging current was 25 mA. The cell was discharged throughan adjustable resistor which was set to 5.5 kΩ so that the initialdischarging current was 0.6 mA. After about 3.4 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.005 g): 0.2LiCl—0.8CaCl₂

Cathode (0.005 g): 0.9LiOCN—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 1.2×10 mm

This cell was prepared from start to finish using the same cellmaterials and fabrication procedures as those of Cell A of this Exampleexcept for the electrolyte which was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 2.2 hours.

The open circuit voltage after charging was 3.60 V, and the maximumshort cut discharging current was 30 mA. The cell was discharged throughan adjustable resistor which was set to 5.3 kΩ so that the initialdischarging current was 0.6 mA. After about 3.3 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #13

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.4. The cathode consists of a saltmixture, xLiSCN+(1−x)AlCl₃, where 0.8<x<0.95. Both electrodes aresupported on carbon fiber cluster substrates. The electrolyte mayconsist of either (1) (1−x)SO₂Cl₂+xLiAlCl₄, where 0.02<x<1.5, or (2)AlCl₃+PCl₅+0.3POCl₃+0.1LiAlCl₄. The fabrication procedures andperformance characteristics of two representative cells (denoted A andB) using this family of cell component materials are given below.

A. Anode (0.005 g): 0.2LiCl—0.8CaCl₂

Cathode (0.005 g): 0.9LiSCN—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

Electrode active material salt mixtures with nominal compositions asgiven above were deposited on the carbon fiber cluster substrates fromaqueous solutions using the technique described above in Part A ofSection IV (Electrode Coating Preparations). About 0.005 g of salt weredeposited on each electrode substrate. For the anode, a solution of 8.9g CaCl₂ and 0.85 g LiCl in 10 ml water was used as the startingsolution. The baking procedure performed between immersions and thefinal baking and annealing steps were the same as those described forthe electrode type 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel, given inPart A(i) of Section IV (Electrode Coating Preparations).

For the cathode, a starting solution of 6.2 g LiSCN and 1.3 g AlCl₃ in20 ml water was used. The baking procedure used between immersionsconsisted of heating the cathode assemblage in vacuum to 100° C.,holding for five hours, cooling to room temperature, placing theassemblage in a vacuum-sealed Pyrex glass tube, heating to 250° C., andholding for five hours. The final heat treatment consisted of placingthe assemblage in a vacuum-sealed Pyrex glass tube, heating to 320° C.,and holding for 30 minutes.

The electrolyte for this cell was prepared by dissolving 7.0 g LiAlCl₄in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of5.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.7 hours.

The open circuit voltage after charging was 3.65 V, and the maximumshort cut discharging current was 25 mA. The cell was discharged throughan adjustable resistor which was set to 5.2 kΩ so that the initialdischarging current was 0.6 mA. After about 2.6 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.005 g): 0.2LiCl—0.8CaCl₂

Cathode (0.005 g): 0.9LiSCN—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 1.2×10 mm

This cell was prepared from start to finish using the same cellmaterials and fabrication procedures as those of Cell A of this Exampleexcept for the electrolyte which was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.6 hours.

The open circuit voltage after charging was 3.50 V, and the maximumshort cut discharging current was 20 mA. The cell was discharged throughan adjustable resistor which was set to 5.0 kΩ so that the initialdischarging current was 0.6 mA. After about 2.5 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #14

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.4. The cathode consists of a saltmixture, xLiClO₄+(1−x)AlCl₃, where 0.8<x<0.95. Both electrodes aresupported on carbon fiber cluster substrates. The electrolyte mayconsist of either (1) (1−x)SO₂Cl₂+xLiAlCl₄, where 0.02<x<1.5, or (2)AlCl₃+PCl₅+0.3POCl₃+0.1LiAlCl₄. The fabrication procedures andperformance characteristics of two representative cells (denoted A andB) using this family of cell component materials are given below.

A. Anode (0.01 g): 0.2LiCl—0.8CaCl₂

Cathode (0.01 g): 0.9LiClO₄—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

Electrode active material salt mixtures with nominal compositions asgiven above were deposited on the carbon fiber cluster substrates fromaqueous solutions using the technique described above in Part A ofSection IV (Electrode Coating Preparations). About 0.01 g of salt weredeposited on each electrode substrate. For the anode, a solution of 8.9g CaCl₂ and 0.85 g LiCl in 10 ml water was used as the startingsolution. For the cathode, a solution of 4.6 g LiClO₄ and 0.6 g AlCl₃ in5 ml water was used. For both electrodes, the baking procedure performedbetween immersions and the final baking and annealing steps were thesame as those described for the electrode type 0.2LiCl—0.8CaCl₂, 4×10mm, carbon-on-nickel, given in Part A(i) of Section IV (ElectrodeCoating Preparations).

The electrolyte for this cell was prepared by dissolving 7.0 g LiAlCl₄in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.9 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 80 mA. The cell was discharged through anadjustable resistor which was set to 6.2 kΩ so that the initialdischarging current was 0.5 mA. After about 3.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.01 g): 0.2LiCl—0.8CaCl₂

Cathode (0.01 g): 0.9LiClO₄—0.1AlCl₃

Substrate: Carbon

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 1.2×10 mm

This cell was prepared from start to finish using the same cellmaterials and fabrication procedures as those of Cell A of this Exampleexcept for the electrolyte which was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 1.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1 mA until it had reached a value ofabout 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.01 mA. The total charging time fromstart to finish was about 1.9 hours.

The open circuit voltage after charging was 3.9 V, and the maximum shortcut discharging current was 85 mA. The cell was discharged through anadjustable resistor which was set to 6.2 kΩ so that the initialdischarging current was 0.5 mA. After about 3.4 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #15

For the cells of this Example, the anode consists of carbon in acarbon-containing substrate. The cathode consists of a salt mixture,0.8Li₂O—0.2Li₂CO₃. Both electrodes substrates consist of carbonreinforced with nickel metal. The electrolyte may consist of either (1)(1−x)SOCl₂+xLiAlCl₄ or (2) (1−x)SO₂Cl₂+xLiAlCl₄, where 0.02<x<1.5. Thefabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.02 g): Carbon

Cathode (0.01 g): 0.8Li₂O—0.2Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.04LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

For the anode, the 0.005 g of carbon on the substrate constituted theanode active material.

An electrode of the type, 0.8Li₂O—0.2Li₂CO₃, 4×10 mm, carbon-on-nickel,prepared by applying the coating as a paste, constituted the cathode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part B(i) of Section IV (ElectrodeCoating Preparations). The total amount of salt applied to the substratewas about 0.01 g.

The electrolyte was prepared by dissolving 7.0 g LiAlCl₄ in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 65 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 7.0 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): Carbon

Cathode (0.01 g): 0.8Li₂O—0.2Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except that SO₂Cl₂ wassubstituted for SOCl₂ in the electrolyte. The electrolyte was preparedby dissolving 7.0 g LiAlCl₄ into 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.4 hours.

The open circuit voltage after charging was 3.65 V, and the maximumshort cut discharging current was 75 mA. The cell was discharged throughan adjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 1.0 mA. After about 6.8 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #16

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.95. The cathode consists of mixture ofLi₂S and carbon. Both electrodes are supported on or carbon-on-nickelsubstrates. The electrolyte may consist of one of

(1−x)SOCl₂+xLiAlCl₄  (1)

(1−x)SO₂Cl₂+xLiAlCl₄  (2)

AlCl₃+PCl₅+0.3PCl₃+0.05LiAlCl₄  (3)

where 0.02<x<1.5 for electrolytes (1) and (2). The fabricationprocedures and performance characteristics of three representative cells(denoted A through C) using this family of cell component materials aregiven below.

A. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.025 g): Li₂S—C

Substrate: Carbon

Electrolyte (in excess): SOCl₂—0.04LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

A cathode containing a mixture of Li₂S and carbon as electrode activematerials was prepared as follows. The starting Li₂S was ground to afine powder with a mortar and pestle. A paste was made by combining 4.6g Li₂S with 2.0 g of a polypropylene oxide-acetonitrile binder. Thisbinder was made in 100 g lots by combining 50 g polypropylene oxide witha molecular weight of about 4,000 g/mole (i.e., PPO_(4,000)) and 50 gacetonitrile. About 0.012-0.013 g of this Li₂S-PPO_(4,000) paste wasapplied evenly to each side of a carbon-nickel substrate which was thensqueezed between a glass roller and a glass plate. The cathodeassemblage was placed into a Pyrex glass tube, heated to 150° C. in air,and held for two hours. The tube containing the assemblage was thencooled to room temperature, vacuum-sealed, reheated to 600° C., held fortwo hours, and cooled slowly to room temperature.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.6 hours.

The open circuit voltage after charging was 3.2 V, and the maximum shortcut discharging current was 70 mA. The cell was discharged through anadjustable resistor which was set to 2.7 kΩ so that the initialdischarging current was 1.0 mA. After about 7.2 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.002 g): 0.2LiCl—0.8CaCl₂

Cathode (0.002 g): Li₂S—C

Substrate: Carbon

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 4×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

An anode active material salt mixture with the nominal composition givenabove was deposited on the carbon fiber cluster substrate from solutionas described above in Part A of Section III (Electrode SubstratePreparations). About 0.002 g of salt was deposited on the anodesubstrate. For the anode, a solution of 8.9 g CaCl₂ and 0.85 g LiCl in10 ml water was used as the starting solution. The baking procedureperformed between immersions and the final baking and annealing stepswere the same as those described for the electrode type0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel, given in Part A(i) ofSection IV (Electrode Coating Preparations).

For the cathode, about 0.002 g of a paste consisting of a Li₂S-carbonmixture was applied to a carbon fiber cluster substrate. This paste wasprepared from start to finish using the same materials and procedures asthose of Cell A of this Example. The subsequent heat treatment was alsothe same as that of Cell A of this Example.

The electrolyte was prepared by dissolving 7.0 g LiAlCl₄ in 136 gSO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 1.0 kΩ. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 3.4 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 80 mA. The cell was discharged through anadjustable resistor which was set to 2.9 kΩ so that the initialdischarging current was 1.0 mA. After about 6.8 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.002 g): 0.2LiCl—0.8CaCl₂

Cathode (0.002 g): Li₂S—C

Substrate: Carbon

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.05LiAlCl₄

Size: 1.2×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell B of this Example except for the electrolytewhich was prepared as follows.

The electrolyte was prepared by dissolving 0.875 g LiAlCl₄ into 38 gAlCl₃—PCl₅—0.3PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3PCl₃ solvent was prepared asdescribed above in Part B(i) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.4 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.5 mA until it had reached a valueof about 150 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 2.7 V, and the maximum shortcut discharging current was 85 mA. The cell was discharged through anadjustable resistor which was set to 2.2 kΩ so that the initialdischarging current was 1.0 mA. After about 5.0 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #17

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of mixture ofLi₂O and carbon. Both electrodes are supported on substrates of carbonreinforced with nickel. The electrolyte solvent may consist of anycomposition within the room temperature liquid phase region of any oneof the following ternaries: (1) AlCl₃+PCl₅+PCl₃; (2) AlCl₃+PCl₅+POCl₃;(3) AlCl₃+PCl₅+PSCl₃. To impart a high Li⁺ ionic conductivity to theelectrolyte, LiAlCl₄ is added at a concentration of about 10 m %.

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A through B) using this family of cellcomponent materials are given below.

A. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.008 g): Li₂O—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

A cathode was prepared as follows. The Li₂O-carbon mixture was preparedby combining 9.6 g LiOH and 2.0 g polypropylene oxide with a molecularweight of 4,000 (i.e., PPO₄₀₀₀). This mixture was placed in a quartztest tube, heated in air to 200° C., held for two hours, heatedthereafter at 5° C./minute to 800° C., held for 30 minutes, and cooledto room temperature. This hard solid mixture of Li₂O and carbon wasground to a fine powder with a mortar and pestle and mixed with 1.0 gPPO₄₀₀₀ to form a paste. Each side of a carbon-on-nickel substrate wascoated with about 0.004 g Li₂O-carbon paste which was smoothed bysqueezing between a glass roller and glass plate. This cathodeassemblage was placed in a large glass test tube with the open endstuffed with glass paste paper, heated in argon at 5° C./minute from100° C. to 250° C., and held for four hours in argon. This assemblagewas heated thereafter in argon at 5° C./minute to 500° C. and held forfour hours.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 38 gAlCl₃—PCl₅—0.3PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3PCl₃ solvent was prepared asdescribed above in Part B(i) of Section II (Electrolyte Preparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.4 kΩ so that the charging current was 1.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.5 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.7 hours.

The open circuit voltage after charging was 3.15 V, and the maximumshort cut discharging current was 50 mA. The cell was discharged throughan adjustable resistor which was set to 3.3 kΩ so that the initialdischarging current was 0.8 mA. After about 7.4 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.008 g): Li₂O—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.4 V across the cell in series with an adjustable resistor which wasinitially set to 2.4 kΩ so that the charging current was 1.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.5 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.9 hours.

The open circuit voltage after charging was 3.20 V, and the maximumshort cut discharging current was 55 mA. The cell was discharged throughan adjustable resistor which was set to 3.2 kΩ so that the initialdischarging current was 0.8 mA. After about 7.6 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #18

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of mixture ofLi₂S and carbon. The electrodes are supported on substrates of carbonreinforced with nickel. The electrolyte solvent may consist of anycomposition within the room temperature liquid phase region of any oneof the following ternaries: (1) AlCl₃+PCl₅+PCl₃; (2) AlCl₃+PCl₅+POCl₃;(3) AlCl₃+PCl₅+PSCl₃. To impart a high Li⁺ ionic conductivity to theelectrolyte, LiAlCl₄ is added at a concentration of about 10 m %.

The fabrication procedures and performance characteristics of threerepresentative cells (denoted A through C) using this family of cellcomponent materials are given below.

A. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): Li₂S—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

A cathode containing a mixture of Li₂S and carbon as electrode activematerials was prepared as follows. The starting Li₂S was ground to afine powder with a mortar and pestle. A paste was made by combining 4.6g Li₂S with 2.0 g of a polypropylene oxide-acetonitrile binder. Thisbinder was made in 100 g lots by combining 50 g polypropylene oxide witha molecular weight of about 4,000 g/mole (i.e., PPO_(4,000)) and 50 gacetonitrile. About 0.006 g of this Li₂S-PPO_(4,000) paste was appliedevenly to each side of a carbon-nickel substrate which then squeezedbetween a glass roller and a glass plate. The cathode assemblage wasplaced into a Pyrex glass tube, heated to 150° C. in air, and held fortwo hours. The tube containing the assemblage was then cooled to roomtemperature, vacuum-sealed, reheated to 600° C., held for two hours, andcooled slowly to room temperature.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 38 gAlCl₃—PCl₅—0.3PCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3PCl₃ solvent was prepared asdescribed above in Part B(i) of Section II (Electrolyte Preparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.3 V across the cell in series with an adjustable resistor which wasinitially set to 1.8 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.4 hours.

The open circuit voltage after charging was 2.5 V, and the maximum shortcut discharging current was 45 mA. The cell was discharged through anadjustable resistor which was set to 2.4 kΩ so that the initialdischarging current was 0.8 mA. After about 7.1 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): Li₂S—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 1.8 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 5.0 hours.

The open circuit voltage after charging was 3.25 V, and the maximumshort cut discharging current was 50 mA. The cell was discharged throughan adjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 0.8 mA. After about 6.8 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.012 g): Li₂S—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PSCl₃—0.1LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

An electrolyte with the nominal composition given above was prepared bydissolving 1.75 g LiAlCl₄ into 39 g AlCl₃—PCl₅—0.3PSCl₃ solvent andheating this mixture to 80° C. until it had homogenized. The startingAlCl₃—PCl₅—0.3PSCl₃ solvent was prepared as described above in PartB(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.4 V across the cell in series with an adjustable resistor which wasinitially set to 1.9 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.5 hours.

The open circuit voltage after charging was 3.20 V, and the maximumshort cut discharging current was 55 mA. The cell was discharged throughan adjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 0.8 mA. After about 7.1 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #19

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of the mixture,xLi₂O+(1−x)Li₂CO₃, where 0.6<x<0.9. The electrodes are supported onsubstrates of carbon reinforced with nickel. The electrolyte solvent mayconsist of any composition within the room temperature liquid phaseregion of any one of the following ternaries: (1) AlCl₃+PCl₅+PCl₃; (2)AlCl₃+PCl₅+POCl₃; (3) AlCl₃+PCl₅+PSCl₃. To impart a high Li⁺ ionicconductivity to the electrolyte, LiAlCl₄ is added at a concentration ofabout 10 m %.

The fabrication procedures and performance characteristics of threerepresentative cells (denoted A through C) using this family of cellcomponent materials are given below.

A. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.001 g): 0.8Li₂O—0.2Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1LiAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

An electrode of the type, 0.8Li₂O—0.2Li₂CO₃, 4×10 mm, carbon-on-nickel,prepared by applying the coating as a paste, constituted the cathode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part B(i) of Section IV (ElectrodeCoating Preparations). The total amount of salt applied to the substratewas about 0.001 g.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.6 kΩ so that the charging current was 1.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.5 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 5.0 hours.

The open circuit voltage after charging was 3.25 V, and the maximumshort cut discharging current was 45 mA. The cell was discharged throughan adjustable resistor which was set to 3.4 kΩ so that the initialdischarging current was 0.8 mA. After about 6.5 hours, the cell outputvoltage had dropped to 0.5 V.

B. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.001 g): 0.8Li₂O—0.2Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ in 39 gAlCl₃—PCl₅—0.3POCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3POCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.6 V across the cell in series with an adjustable resistor which wasinitially set to 2.6 kΩ so that the charging current was 1.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.5 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 5.4 hours.

The open circuit voltage after charging was 3.25 V, and the maximumshort cut discharging current was 45 mA. The cell was discharged throughan adjustable resistor which was set to 3.4 kΩ so that the initialdischarging current was 0.8 mA. After about 7.8 hours, the cell outputvoltage had dropped to 0.5 V.

C. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.001 g): 0.8Li₂O—0.2Li₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PSCl₃—0.1LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for the electrolytewhich was prepared as follows.

The electrolyte was prepared by dissolving 1.75 g LiAlCl₄ into 39 gAlCl₃—PCl₅—0.3PSCl₃ solvent and heating this mixture to 80° C. until ithad homogenized. The starting AlCl₃—PCl₅—0.3PSCl₃ solvent was preparedas described above in Part B(ii) of Section II (ElectrolytePreparations).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.6 kΩ so that the charging current was 1.5 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 1.5 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.03 mA. The total charging time fromstart to finish was about 5.1 hours.

The open circuit voltage after charging was 3.25 V, and the maximumshort cut discharging current was 40 mA. The cell was discharged throughan adjustable resistor which was set to 3.5 kΩ so that the initialdischarging current was 0.8 mA. After about 7.6 hours, the cell outputvoltage had dropped to 0.5 V.

EXAMPLE #20

For the cells of this Example, the anode consists of a salt mixture,xLiCl+(1−x)CaCl₂, where 0.2<x<0.5. The cathode consists of the saltmixture of xLi₂S+(1−x)LiCl, where 0.6<x<0.9. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte consists of either (1) xLiAlCl₄+(1−x)SOCl₂ or (2)xLiAlCl₄+(1−x)SO₂Cl₂ where for both electrolytes, x may range from about0.02 to 1.5. The fabrication procedures and performance characteristicsof two representative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.01 g): 0.8Li₂S—0.2LiCl

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.04LiAlCl4

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type II(carbon-Teflon paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart C of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.2LiCl—0.8CaCl₂, 4×10 mm, carbon-on-nickel,prepared by a solution deposition technique, constituted the anode forthis cell. The materials and preparation procedures for this electrodeare described above in detail in Part A(i) of Section IV (ElectrodeCoating Preparations).

The cathode was prepared as follows. The starting Li₂S was ground to afine powder with a mortar and pestle. A paste containing Li₂S and LiClin a ˜4:1 molar ratio was prepared by combining 3.7 g Li₂S and 0.84 gLiCl with a polyethylene-water binder containing 0.5 g polyethyleneoxide with a molecular weight of 1,000,000 (i.e., PEO₁₀₀₀₀₀₀). (Thisbinder was made by dissolving 0.5 g PEO₁₀₀₀₀₀₀ into 50 ml water and thenallowing most of the water to evaporate until only about 5 ml remained).This paste was heated to 100° C. in air and held for about two hours todrive off excess water. About 0.005 g of this paste was applied evenlyto each side of a carbon-on-nickel substrate which was then squeezedbetween a glass roller and a glass plate. The cathode assemblage washeated in air at a rate of 5° C./minute from 50° C. to 160° C. and heldfor two hours. A vacuum was applied, and the assemblage was heatedfurther to 200° C. and held for another two hours. The cathodeassemblage was cooled to room temperature and placed into a glass testtube which was vacuum-sealed. This assemblage was heated at a rate of 5°C./minute to 450° C., held for about five hours, and cooled slowly toroom temperature.

The electrolyte was prepared by dissolving 7.0 g LiAlCl₄ in 120 g SOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 1.5 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 60 mA. The cell was discharged through anadjustable resistor which was set to 3.1 kΩ so that the initialdischarging current was 1.0 mA. After about 5.2 hours, the cell outputvoltage had dropped to 0.5 V. During discharging, the cell outputvoltage exhibited two plateaus.

B. Anode (0.02 g): 0.2LiCl—0.8CaCl₂

Cathode (0.01 g): 0.8Li₂S—0.2LiCl

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.04LiAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell A of this Example except for theelectrolyte, in which SO₂Cl₂ was substituted for SOCl₂. The electrolytewas prepared by dissolving 7.0 g LiAlCl₄ in 136 g SO₂Cl₂.

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.7 hours.

The open circuit voltage after charging was 3.8 V, and the maximum shortcut discharging current was 60 mA. The cell was discharged through anadjustable resistor which was set to 3.5 kΩ so that the initialdischarging current was 1.0 mA. After about 5.2 hours, the cell outputvoltage had dropped to 0.5 V. During discharging, the cell outputvoltage exhibited two plateaus, as for Cell A of this Example.

EXAMPLE #21

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. the cathode consists of asalt mixture, xNaCl+(1−x)NaF, where 0.6<x<0.95. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of any one of

AlCl₃+PCl₅+0.3PCl₃+0.1NaAlCl₄  (1)

AlCl₃+PCl₅+0.3POCl₃+0.1NaAlCl₄  (2)

AlCl₃+PCl₅+0.3PSCl₃+0.1NaAlCl₄  (3)

The fabrication procedures and performance characteristics of threerepresentative cells (denoted A through C) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.85NaCl—0.15NaF

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (electrode Coating Preparations).

A cathode with the nominal composition given above was prepared asfollows. NaCl and NaBF₄ were combined in an 85:15 molar ratio bydissolving 4.90 g NaCl and 1.62 g NaBF₄ in water as a saturated solutionat 40° C. (To make this solution, water was added to the salt mixturewhile stirring with a magnetic stirrer on a hot plate until all thesolids had dissolved.) This salt mixture was deposited from solution asa coating on a carbon-on-nickel substrate using the technique describedabove in Part A of Section IV (Electrode Coating Preparations). Thebaking procedure performed after each immersion was the same as thatused for the anode, i.e., as described above in Part A(ii) of Section IV(Electrode Coating Preparations). This baking procedure served to driveoff all the water and also insured the complete conversion of NaBF₄ toNaF by inducing the decomposition of NaBF₄ to NaF and gaseous BF₃. Theimmersion-baking procedure was repeated as necessary until the totalweight of the salt coating was about 0.025 g.

An AlCl₃—PCl₅—PCl₃—NaAlCl₄ electrolyte with the above nominalcomposition was prepared by dissolving 9.6 g NaAlCl₄ into 195 gAlCl₃—PCl₅—0.3PCl₃ at room temperature. The starting NaAlCl₄ salt wasprepared as described above in Section I (Starting MaterialsPreparations). The starting AlCl₃—PCl₅—0.3PCl₃ solvent was prepared asdescribed above in Part B(i) of Section II (Electrolyte Preparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 2.8 kΩ so that the initialdischarging current was 1.0 mA. After about 5.2 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.85NaCl—0.15NaF

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1NaAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as Cell A of this Example except that for the electrolyte,POCl₃ was substituted for PCl₃. The electrolyte was prepared bydissolving 9.6 g NaAlCl₄ into 210 g AlCl₃—PCl₅—0.3POCl₃. The startingAlCl₃—PCl₅—0.3POCl₃ solvent was prepared as described above in PartB(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 4.0 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 2.8 kΩ so that the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

C. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.85NaCl—0.15NaF

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PSCl₃—0.1NaAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures a Cell A of this Example except that for the electrolyte,PSCl₃ was substituted for PCl₃. The electrolyte was prepared bydissolving 3.8 g NaAlCl₄ into 78 g AlCl₃—PCl₅—0.3PSCl₃. The startingAlCl₃—PCl₅—0.3PSCl₃ solvent was prepared as described above in PartB(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ sot hat the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #22

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNaCl+(1−x)Na₂O, where 0.6<x<0.95. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of either

AlCl₃+PCl₅+0.3PCl₃+0.1NaAlCl₄  (1)

AlCl₃+PCl₅+0.3POCl₃+0.1NaAlCl₄  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.7NaCl—0.3Na₂O

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (electrode Coating Preparations).

A cathode with the nominal composition given above was prepared asfollows. NaCl and NaOH were combined in a 7:6 molar ratio by dissolving4.90 g NaCl and 4.20 g NaOH in water as a saturated solution at roomtemperature. (To make this solution, water was added to the salt mixturewhile stirring with a magnetic stirrer until all the solids haddissolved.) This salt mixture was deposited from solution as a coatingon a carbon-on-nickel substrate using the technique described above inPart A of Section IV (Electrode Coating Preparations). The bakingprocedure performed after each immersion consisted of first drying thecoated substrate by heating in air at a rate of about 5° C./minute from50° C. to 100° C. and holding for one hour. Then, the coated substratewas heated to 190° C., held for two hours, heated thereafter at a rateof 10° C./minute to 500° C. and held for about 10 hours. This bakingprocedure served to drive off all the water and also insured thecomplete conversion of NaOH to Na₂O by inducing the decomposition ofNaOH to Na₂O and H₂O. The immersion-baking procedure was repeated asnecessary until the total weight of the salt coating was about 0.025 g.

The electrolyte was prepared by dissolving 9.6 g NaAlCl₄ into 195 gAlCl₃—PCl₅—0.3PCl₃ at room temperature. The AlCl₃—PCl₅—0.3PCl₃ solventwas prepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and parepation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.2 across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 500 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.8 hours.

The open circuit voltage after charging was 3.2 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.7NaCl—0.3Na₂O

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3POCl₃—0.1NaAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as used for Cell A of this Example except that POCl₄ wassubstituted for PCl₃ in the electrolyte. The electrolyte was prepared bydissolving 9.6 g NaAlCl₄ into 210 g AlCl₃—PCl₅—0.3POCl₃. TheAlCl₃—PCl₅—0.3POCl₃ solvent was prepared as described above in PartB(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.2 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.6 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #23

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNaOCN+(1−x)Al₂O₃, where 0.9<x<0.95. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of either

AlCl₃+PCl₅+0.3PCl₃+0.02NaAlCl₄+0.025NaAl(OCN)Cl₃  (1)

AlCl₃+PCl₅+0.3POCl₃+0.02NaAlCl₄+0.025NaAl(OCN)Cl₃  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaOCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess):AlCl₃—PCl₅—0.3PCl₃—0.02NaAlCl₄—0.025NaAl(OCN)Cl₃

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

A cathode with the nominal composition given above was prepared asfollows. A starting solution of NaOCN and AlCl₃ present in a 95:10 molarratio was prepared by dissolving 6.2 g NaOCn and 1.3 g AlCl₃ in 40 mlwater at 80° C. This salt mixture was deposited from solution on acarbon-on-nickel substrate using the technique described above in Part Aof Section IV (Electrode Coating Preparations). The baking procedureperformed after each immersion was the same as that used for the anode,i.e., as described above in Part A(ii) of Section IV (Electrode CoatingPreparations). The immersion-baking procedure was repeated as necessaryuntil the total weight of the salt coating was about 0.025 g.

The electrolyte was prepared by dissolving 4.8 g NaAlCl₄ and 2.5 gNaAl(OCN)Cl₃ into 215 g AlCl₃—PCl₅—0.3PCl₃ at room temperature. Thestarting NaAlCl₄ and NaAl(OCN)Cl₃ salts were prepared as described abovein Section I (Starting Materials Preparations). The AlCl₃—PCl₅—0.3PCl₃solvent was prepared as described above in Part B(i) of Section II(Electrolyte Preparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 300 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.4 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.6 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaOCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess):AlCl₃—PCl₅—0.3POCl₃—0.02NaAlCl₄—0.025NaAl(OCN)Cl₃

Size: 4×10 mm

This cell was prepared from start to finish using the same procedures asdescribed above for Cell A of this Example except that POCl₃ wassubstituted for PCl₃ in the electrolyte. The electrolyte for this cellwas prepared by dissolving 4.8 g NaAlCl₄ and 2.5 g NaAl(OCN)Cl₃ into 230g AlCl₃—PCl₅—0.3POCl₃ at room temperature. The AlCl₃—PCl₅—0.3POCl₃solvent was prepared as described above in Part B(ii) of Section II(Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.4 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.2 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #24

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNaSCN+(1−x)Al₂O₃, where 0.9<x<0.95. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of either

AlCl₃+PCl₅+0.3PCl₃+0.02NaAlCl₄+0.02NaAl(SCN)Cl₃  (1)

AlCl₃+PCl₅+0.3POCl₃+0.02NaAlCl₄+0.025NaAl(SCN)Cl₃  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaSCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.02NaAlCl₄—0.02NaAl(SCN)Cl₃

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

A cathode with the nominal composition given above was prepared asfollows. A starting solution of NaSCN and AlCl₃ present in a 95:10 molarratio was prepared by dissolving 7.8 g NaSCN and 1.3 g AlCl₃ in 40 mlwater at 80° C. This salt mixture was deposited from solution on acarbon-on-nickel substrate using the technique described above in Part Aof Section IV (Electrode Coating Preparations). The baking procedureperformed after each immersion was the same as that used for the anode,i.e., as described above in Part A(ii) of Section IV (Electrode CoatingPreparations). The immersion-baking procedure was repeated as necessaryuntil the total weight of the salt coating was about 0.025 g.

The electrolyte was prepared by dissolving 4.8 g NaAlCl₄ and 2.5 gNaAl(SCN)Cl₃ into 215 g AlCl₃—PCl₅—0.3PCl₃. The starting NaAlCl₄ andNaAl(SCN)Cl₃ salts were prepared as described above in Section I(Starting Materials Preparations). The AlCl₃—PCl₅—0.3PCl₃ solvent wasprepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.5 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaSCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess):AlCl₃—PCl₅—0.3POCl₃—0.02NaAlCl₄—0.025NaAl(SCN)Cl₃

Size: 4×10 mm

This cell was prepared from start to finish using the same procedures asdescribed above for Cell A of this Example except that POCl₃ wassubstituted for PCl₃ in the electrolyte. The electrolyte for this cellwas prepared by dissolving 4.8 g NaAlCl₄ and 2.5 g NaAl(SCN)Cl₃ into 230g AlCl₃—PCl₅—0.3POCl₃. The AlCl₃—PCl₅—0.3POCl₃ solvent was prepared asdescribed above in Part B(ii) of Section II (Electrolyte Preparations).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.2 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #25

Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.6Na₂O—0.4Na₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The electrolyte was prepared by dissolving 9.6 g NaAlCl₄ into 195 gAlCl₃—PCl₅—0.3PCl₃ at room temperature. The AlCl₃—PCl₅—0.3PCl₃ solventwas prepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cathode with the nominal composition given above was prepared asfollows. A starting saturated solution of Na₂CO₃ was prepared bydissolving 50 g Na₂CO₃ in 100 ml water at 100° C., cooling to roomtemperature, and separating the undissolved Na₂CO₃ from the solution.About 0.043 g Na₂CO₃ was deposited from solution as a coating on acarbon-on-nickel substrate using the technique described above in Part Aof Section IV (Electrode Coating Preparations). After the final bakingat 250° C., the coated substrate was cooled to room temperature,inserted into a quartz tube, and vacuum-sealed. This assemblage washeated from 100° C. to 1000° C. at 20° C./minute and held for a totalannealing time of 30 minutes. At this temperature, the rate ofdecomposition of Na₂CO₃ to Na₂O and CO₃ is sufficiently high, and theamount of CO₂ driven off as a function of heating time determines therelative amounts of Na₂O and Na₂CO₃ present in the mixture. The totaltime at which the cathode for this cell was held at 1000° C. (i.e., 30minutes) was such that the final coating weight was about 0.025 g,corresponding to a mixture calculated from the weight loss at 0.015 gNa₂O and 0.01 g Na₂CO₃.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 35 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.6 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #26

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNaCl+(1−x)NaF, where 0.6<x<0.95. The electrodes aresupported on substrates on either carbon fibers or substrates of carbonreinforced with nickel. The electrolyte may consist of either

SOCl₂+0.1NaAlCl₄  (1)

SO₂Cl₂0.1NaAlCl₄  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A through C) using this family of cellcomponent materials are given below.

A. Anode (0.006 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.006 g): 0.85NaCl—0.15NaF

Substrate: Carbon

Electrolyte (0.01 g): SOCl₂—0.1NaAlCl₄

Size: 1.2×10 mm

For this cell, the Tiny Cell design was used which is described above inPart A of Section V (Cell Assembly). The materials and preparationsprocedures for the carbon fiber cluster substrate-lead assemblages usedin this test cell design are also given therein.

Electrode active material salt mixtures with nominal compositions asgiven above were deposited from solution on the carbon fiber clustersubstrates using the technique described above in Part A of Section IV(Electrode Coating Preparations). About 0.006 g of salt was deposited oneach electrode substrate. The anode starting solution was made bydissolving 5.8 g NaCl, 13.3 g AlCl₃, and 10.4 g BaCl₂ in water as asaturated solution at 40° C. by adding water to the salt mixture whilestirring until all the solids had dissolved. The cathode startingsolution was made by dissolving 4.90 g NaCl and 1.62 g NaBF₄ in water asa saturated solution at 40° C. by adding water to the salt mixture whilestirring until all the solids had dissolved. For both electrodes, thebaking procedure performed between immersions and the final baking andannealing steps were the same as those described for the electrode type0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm, carbon-on-nickel, given in PartA(ii) of Section IV (Electrode Coating Preparations).

The electrolyte was prepared in a dry box by dissolving 19.2 g NaAlCl₄into 120 g SOCl₂. It was estimated that 0.01 g effective electrolyte wasinserted between the electrodes and other electrolytes were set a bottomof the glass tube.

The cell was charged in constant-voltage mode at a voltage of 4.4 V. A4.0 Ω resistor was connected in series to limit the charging current toabout 2.0 mA. The cell was discharged in constant-current mode at acurrent of 0.1 mA. The cell charging and discharging processes were bothcomputer-controlled.

FIG. 13 shows the cell voltage versus time during charging anddischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., 0.1 mA) (9.5 h)/(0.003 g+0.003 g)=158mAh/g, where 0.003 g is the amount of working electrode active materialon each electrode. The cathode discharging Coulombic capacity wasdetermined from the current, time, and weight of the total workingcathode active material, i.e., (0.1 mA) (9.5 h)/(0.003 g)=317 mAh/g.

B. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.85NaCl—0.15NaF

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, 4×10 mm, Type III(carbon-PPO paste) were used for both electrodes. The materials andpreparation procedures for this substrate design are described above inPart D of Section III (Electrode Substrate Preparations).

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared as follows. NaCl and NaBF₄ were combined in an85:15 molar ratio by dissolving 4.90 g NaCl and 1.62 g NaBF₄ in water asa saturated solution at 40° C. (To make this solution, water was addedto the salt mixture while stirring with a magnetic stirrer on a hotplate until all the solids had dissolved.) This salt mixture wasdeposited from solution as a coating on a carbon-on-nickel substrateusing the technique described above in Part A of Section IV (ElectrodeCoating Preparations). The baking procedure performed after eachimmersion was the same as that used for the anode, i.e., as describedabove in Part A(ii) of Section IV (Electrode Coating Preparations). Thisbaking procedure served to drive off all the water and also insured thecomplete conversion of NaBF₄ to NaF by inducing the decomposition ofNaBF₄ to NaF and gaseous BF₃. The immersion-baking procedure wasrepeated as necessary until the total weight of the salt coating wasabout 0.025 g.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged on constant-voltage mode by applying a voltage of4.2 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.3 V, and the maximum shortcut discharging current was 45 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

C. Anode (0.03 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.03 g): 0.85NaCl—0.15NaF

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.1NaAlCl₄

Size: 4×10 mm

This cell was prepared from start to finish using the same materials andprocedures as those of Cell B of this Example, but with the followingmedications. For the electrodes, the amounts of electrode activematerials deposited on the substrates were slightly larger (i.e., 0.03rather than 0.025 g). Also, SOCl₂ was substituted for SO₂Cl₂ in theelectrolyte which, for this cell, was prepared by dissolving 19.2 gNaAlCl₄ into 120 g SOCl₂.

This cell was charged by a DC power source in constant-current mode at2.0 mA. The charging voltage started at 1.0 V and increased to 4.0 Vafter about 45 minutes. The charging process was continued until thecharging voltage reached its upper limit of 4.5 V. At that point, aconstant current could not be maintained and the charging currentgradually decreased to 1.0 mA over a four hour period, at which point,the charging process was stopped. The open circuit voltage aftercharging was 3.8 V.

The cell was discharged through an adjustable resistor with a resistanceof about 450 Ω for a discharging current value of about 0.7 mA. Thedischarging process was continued for about 8.7 hours at which point,the cell output voltage had dropped to 1.0 V with an output current of0.2 mA. At that point, the cell open circuit voltage was measured atabout 2.8 V.

FIG. 14a shows the cell voltage and current versus time duringdischarging. FIG. 14b shows the cell output power versus time duringdischarging. The discharging Coulombic capacity of the cell wasdetermined from the current, time, and weight of the total workingelectrode active material, i.e., (0.65 mA) (8.7 h)/(0.015 g+0.015 g)=189mAh/g, where 0.015 g as the amount of working electrode active materialon each electrode. The discharging Coulombic capacity for each electrodewas determined from the current, time, and weight of the total workingelectrode active material for each electrode, i.e., (0.65 mA) (8.7h)/(0.015 g)=377 mAh/g.

EXAMPLE #27

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNaCl+(1−x)Na₂O, where 0.4<x<0.9. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of either

SOCl₂+0.1NaAlCl₄  (1)

SO₂Cl₂0.1NaAlCl₄  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.6NaCl—0.4Na₂O

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared as follows. NaCl and NaOH were combined in a3:4 molar ratio by dissolving 4.90 g NaCl and 4.47 g NaOH in water as asaturated solution at room temperature. (To make this solution, waterwas added to the salt mixture while stirring with a magnetic stirreruntil all the solids had dissolved.) This salt mixture was depositedfrom solution as a coating on a carbon-on-nickel substrate using thetechnique described above in Part A of Section IV (Electrode CoatingPreparations). The baking procedure performed after each immersionconsisted of first drying the coated substrate by heating in air at arate of about 5° C./minute from 50° C. to 100° C. and holding for onehour. Then, the coated substrate was heated to 190°0 C., held for twohours, heated thereafter at a rate of 10° C./minute to 500° C. and heldfor about 10 hours. This baking procedure served to drive off all thewater and also insured the complete conversion of NaOH to Na₃O byinducing the decomposition of NaOH to Na₂O and H₂O. The immersion-bakingprocedure was repeated as necessary until the weight of the salt coatingwas about 0.025 g.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 120 gSOCl₂.

a cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 60 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.016 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.154 g): 0.6NaCl—0.4Na₂O

Substrate: Carbon-on-nickel

Electrolyte (20 g): SO₂Cl₂—0.1NaAlCl₄

Size: 50×70 mm

For this cell, carbon-on-nickel substrates, 50×70 mm, Type II(carbon-acetonitrile-PPO slurry) were used for both electrodes. Thematerials and preparation procedures for this substrate design aredescribed above in Part E of Section III (Electrode SubstratePreparations).

The anode was prepared by applying a salt coating with the above nominalcomposition using a solution deposition technique as described above inPart A of Section IV (Electrode Coating Preparations). The total amountof salt deposited on the anode substrate was about 0.16 g. The anodestarting solution was made by dissolving 5.8 g NaCl, 13.3 g AlCl₃, and10.4 g BaCl₂ in water as a saturated solution at 40° C. by adding waterto the salt mixture while stirring until all the solids had dissolved.The baking procedure performed between immersions and the final bakingand annealing steps were the same as those described for the electrodetype 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm, carbon-on-nickel, given inPart A(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared using the same procedures as those of Cell A ofthis Example except that the total amount of salt applied to thesubstrate was 0.154 g rather than 0.025 g due to the larger substratesize.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing the Jelly-roll test cell design. The materials and preparationprocedures for this test cell design are described in Part D of SectionV (Cell Assembly).

The cell was charged in constant-current mode at a high rate for 30minutes. The cell was discharged in constant-current mode at 20 mA forabout 1.7 hours. FIG. 15 shows the cell voltage versus time duringdischarging.

The discharging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (20 mA) (1.7 h)/(0.16 g+0.154 g)=108 mAh/g. The cathodedischarging Coulombic capacity was determined from the current, time,and weight of the total working cathode active material, i.e., (20 mA)(1.7 h)/(0.154 g)=221 mAh/g. For this jelly-roll test cell design, thetotal working electrode active material included the material on bothsides of the substrates.

EXAMPLE #28

For the cells of this Example, the anode consists of a salt mixture,xNaCl+(1−x)Al₂O₃+0.2BaCl₂, where 0.5<x<0.7. The cathode consists of asalt mixture, xNa₂O+(1−x)Na₂CO₃, where x>0.6. The electrodes aresupported on substrates of carbon reinforced with nickel. Theelectrolyte may consist of either

SOCl₂+0.1NaAlCl₄  (1)

SO₂Cl₂0.1NaAlCl₄  (2)

The fabrication procedures and performance characteristics of tworepresentative cells (denoted A and B) using this family of cellcomponent materials are given below.

A. Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.6Na₂O—0.4Na₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared as follows. A starting solution of Na₂CO₃ wasprepared by dissolving 50 g Na₂CO₃ in 100 ml water at 100° C., coolingto room temperature, and separating the undissolved Na₂CO₃ from thesolution. About 0.043 g Na₂CO₃ was deposited from solution on acarbon-on-nickel substrate using the technique described above in Part Aof Section IV (Electrode Coating Preparations). After the final bakingat 250° C., the coated substrate was cooled to room temperature,inserted into a quartz tube, and vacuum-sealed. This assemblage washeated from 100° C. to 1000° C. at 20° C./minute and held for a totalannealing time of 30 minutes so that the Na₂CO₃ would undergo partialdecomposition to Na₂O and CO₂. the total time at which the cathode washeld at 1000° C. (i.e., 30 minutes) was such that the final coatingweight was about 0.025 g, corresponding to a mixture calculated from theweight loss at 0.015 g Na₂O and 0.01 g Na₂CO₃.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 120 gSOCl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this cell design are describedin Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 60 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 5.8 hours, the cell outputvoltage had dropped to 0.3 V.

B. Anode (0.15 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.154 g): 0.6Na₂O—0.4Na₂CO₃

Substrate: Carbon-on-nickel

Electrolyte (20 g): SO₂Cl₂—0.1NaAlCl₄

Size: 40×50 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 50×70 mm, Type IV (carbon-acetonitrile-PPOslurry) described above in Part E of Section III (Electrode SubstratePreparations) with the following modifications: i) the substrate sizewas 40×50 mm rather than 50×70 mm and ii) seven nickel wires were evenlydistributed along the entire length of one of the 40 mm edges from oneend to the other (i.e., rather than five wires along one of the 50 mmedges, as in the 50×70 mm substrate).

The anode was prepared by applying a salt coating with the above nominalcomposition using a solution deposition technique as described above inPart A of Section IV (Electrode Coating Preparations). The total amountof salt deposited on the anode substrate was about 0.15 g. The anodestarting solution was made by dissolving 5.8 g NaCl, 13.3 g AlCl₃, and10.4 g BaCl₂ in water as a saturated solution at 40° C. by adding waterto the salt mixture while stirring until all the solids had dissolved.The baking procedure performed between immersions and the final bakingand annealing steps were the same as those described for the electrodetype 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm, carbon-on-nickel, given inPart A(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared using the same procedures as those of Cell A ofthis Example except that the total amount of salt applied to thesubstrate was 0.154 g rather than 0.025 g due to the larger substratesize.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing the Jelly-roll test cell design. The materials and preparationprocedures for this test cell design are described in Part D of SectionV (Cell Assembly). For the cell described herein, the jelly-roll wasformed by winding the electrode sandwich around the glass center rodwhich was affixed along one of the 50 mm edges.

The cell was charged in constant-current mode at a high rate for 30minutes. The cell was discharged in constant-current mode at 10 mA forabout 5.0 hours. FIG. 16 shows the cell voltage versus time duringdischarging.

The discharging Coulombic capacity of the cell was determined from thecurrent, time, and weight of the total working electrode activematerial, i.e., (10 mA) (5.0 h)/(0.15 g+0.154 g)=165 mAh/g. The cathodedischarging Coulombic capacity was determined from the current, time,and weight of the total working cathode active material, i.e., (10 mA)(5.0 h)/(0.154 g)=325 mAh/g. For this jelly roll design, the totalworking electrode active material included the material on both sides ofthe substrates.

EXAMPLE #29

Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaOCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared as follows. A starting solution of was made bydissolving 6.2 g NaOCN and 1.3 g AlCl₃ in 40 ml water at 80° C. Thissalt mixture was deposited from solution on a carbon-on-nickel substrateusing the technique described above in Part A of Section IV (ElectrodeCoating Preparations). The baking procedure performed after eachimmersion was the same as that used for the anode, i.e., as describedabove in Part A(ii) of Section IV (Electrode Coating Preparations). Theimmersion-baking procedure was repeated as necessary until the totalweight of the salt coating was about 0.025 g.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this cell design are describedin Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.6 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 5.1 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #30

Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): 0.95NaSCN—0.05Al₂O₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode was prepared as follows. A starting solution of was made bydissolving 7.8 g NaSCN and 1.3 g AlCl₃ in 40 ml water at 80° C. Thissalt mixture was deposited from solution on a carbon-on-nickel substrateusing the technique described above in Part A of Section IV (ElectrodeCoating Preparations). The baking procedure performed after eachimmersion was the same as that used for the anode, i.e., as describedabove in Part A(ii) of Section IV (Electrode Coating Preparations). Theimmersion-baking procedure was repeated as necessary until the totalweight of the salt coating was about 0.025 g.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this cell design are describedin Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 3.7 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 3.0 kΩ so that the initialdischarging current was 1.0 mA. After about 4.8 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #31

Anode (0.025 g): 0.5NaCl—0.25Al₂O₃—0.25BaCl₂

Cathode (0.025 g): Na₂S—C

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.1NaAlCl₄

Size: 4×10 mm

For this cell, the carbon-on-nickel substrates were prepared from startto finish using the same materials and procedures as those of thecarbon-on-nickel substrate, 4×10 mm, Type II (carbon-Teflon paste)described above in Part C of Section III (Electrode SubstratePreparations) with one modification: the carbon was combined with 0.4 gTeflon-water paste rather than 0.2 g as originally specified.

An electrode of the type, 0.5NaCl—0.25Al₂O₃—0.25BaCl₂, 4×10 mm,carbon-on-nickel, prepared by a solution deposition technique,constituted the anode for this cell. The materials and preparationprocedures for this electrode are described above in detail in PartA(ii) of Section IV (Electrode Coating Preparations).

The cathode containing a mixture of well dried Na₂S and carbon aselectrode active materials was prepared as follows. The starting Na₂Swas ground to a fine powder with a mortar and pestle. A paste was madeby combining 4.6 g Na₂S with 2.0 g polypropylene oxide-acetonitrilebinder. This binder was made in 100 g lots by combining 50 gpolypropylene oxide with a molecular weight of about 4,000 g/mole (i.e.,PPO_(4,000)) and 50 g acetonitrile. About 0.012-0.013 g of thisNa₂S—PPO_(4,000) paste was applied evenly to each side of acarbon-nickel substrate which was then squeezed between a glass rollerand a glass plate. The cathode assemblage was placed into a Pyrex glasstube, heated to 150° C. in air, and held for two hours. The tubecontaining the assemblage was then cooled to room temperature,vacuum-sealed, reheated to 600° C., held for two hours, and cooledslowly to room temperature.

The electrolyte was prepared by dissolving 19.2 g NaAlCl₄ into 135 gSO₂Cl₂.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this cell design are describedin Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 200 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 3.5 hours.

The open circuit voltage after charging was 2.9 V, and the maximum shortcut discharging current was 25 mA. The cell was discharged through anadjustable resistor which was set to 2.6 kΩ so that the initialdischarging current was 1.0 mA. After about 6.5 hours, the cell outputvoltage had dropped to 0.3 V.

EXAMPLE #32

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.4MgCl₂—0.6Mg(ClO₄)₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—0.02MgCl₂—0.06AlCl₃

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

The cathode was made as follows. A mixture of 3.6 g MgCl₂ and 7.4 gMg(ClO₄)₂ was dried by heating it in air to 250° C. and holding it for10 hours. After cooling it to room temperature, the mixture wasdissolved in 50 g anhydrous acetonitrile which was then driven off byheating to 90° C. This acetonitrile dissolution-evaporation procedurewas repeated three times to rid the powder mixture of any last traces ofwater. It was found to be extremely important to prepare the materialsin as anhydrous a state as possible using techniques such as thosedescribed herein, because small amounts of water in combination withmetal perchlorates such as Mg(ClO₄)₂ can be explosive even during mildheat treatments (e.g., 100-200° C.).

A coating of MgCl₂—Mg(ClO₄)₂ with the above nominal composition wasapplied to the substrate using a solution deposition technique asdescribed above in Part A of Section IV (Electrode CoatingPreparations). the anhydrous powders prepared as described above weredissolved in 50 g acetonitrile, and a coating of 0.05 g was built up onthe substrate by repeated immersion-baking steps. The baking procedurein this case consisted of heating the cathode assemblage in vacuum to150° C. and holding it for 5 hours. This procedure served to drive offany last traces of acetonitrile and water.

The electrolyte was prepared by first dissolving 8.0 g AlCl₃ into 135 gSO₂Cl₂ at room temperature. After that reaction had proceeded tocompletion, 1.9 MgCl₂ was then dissolved into the mixture at 50° C.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test design are describedin Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of3.8 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 250 Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstate to finish was about 4.5 hours.

The open circuit voltage after charging was 2.8 V. The cell wasdischarged through an adjustable resistor which was set to 2.5 kΩ sothat the initial discharging current was 1.0 mA. After about 7.5 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #33

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.4MgO—0.6MgCO₃

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.02MgCl₂—0.06AlCl₃

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

The cathode was prepared as follows. First, MgCO₃ was prepared by an ionexchange process from aqueous solutions of Na₂CO₃ and Mg(NO₃)₂. TheNa₂CO₃ aqueous solution was prepared by dissolving 8.3 g Na₂CO₃ into 100ml water. The Mg(NO₃)₂ aqueous solution was prepared by dissolving 14.8g Mg(NO₃)₂ into 100 ml water. The two solutions were mixed together andallowed to sit for two hours under ambient conditions to enable thecomplete exchange between Na and Mg to occur on the nitrate andcarbonate. Once the MgCO₃ had precipitated out of solution, it waswashed thoroughly and allowed to dry in air under ambient conditions. Abinder was made by dissolving 0.5 g polyethylene oxide with a molecularweight of 1,000,000 (i.e., PEO₁₀₀₀₀₀₀) into 20 ml water and thenallowing most of the water to evaporate until only about 5 ml remained.The entire MgCO₃ precipitate was added, and all ingredients werethoroughly combined to form a paste. About 0.025 g of this paste wasevenly applied to each side of the carbon-on-nickel substrate and thensmoothed by squeezing between a glass roller and glass plate. Thecathode assemblage was transferred to a vacuum oven preset to 200° C.,held for two hours, cooled to room temperature, and transferred to aquartz tube which was then vacuum-sealed. This assemblage was heatedfrom 100° C. to 800° C. at 10° C./minute and held for one hour. Thisfinal heat treatment served to induce partial decomposition of MgCO₃ toMgO and CO₂, and the desired molar ratio of MgO and MgCO₃ was obtainedby adjusting the total heat treatment time at 800° C. After this heattreatment was complete, a weight check was performed to confirm that thetotal weight of the 0.4MgO—0.6MgCO₃ was about 0.05 g.

The electrolyte was prepared by first dissolving 8.0 g AlCl₃ into 120 gSOCl₂ at room temperature. After that reaction had proceeded tocompletion, 19 g MgCl₂ was then dissolved into the mixture at 50° C.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.0 V across the cell in series with an adjustable resistor which wasinitially set to 2.0 kΩ so that the charging current was 4.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 4.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 5.5 hours.

The open circuit voltage after charging was 2.8 V. The cell wasdischarged through an adjustable resistor which was set to 1.5 kΩ sothat the initial discharging current was 1.0 mA. After about 7.0 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #34

Anode (0.2 g): Carbon

Cathode (0.02 g): CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.02CaCl₂

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

For the cathode, a CaCl₂ coating was deposited on the substrate usingthe technique described above in Part A of Section IV (Electrode CoatingPreparations). A total of about 0.02 g of CaCl₂ was deposited on thecathode substrate. The starting solution was 20 ml of water saturatedwith CaCl₂. The baking procedure performed between immersions and thefinal baking and annealing steps are above given in Part A(i) of SectionIV (Electrode Coating Preparations).

The electrolyte was made by dissolving 1.1 g CaCl₂ into 192 gAlCl₃—PCl₅—0.3PCl₃ at 50° C. The starting AlCl₃—PCl₅—0.3PCl₃ solvent wasprepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 1.5 hours.

The open circuit voltage after charging was 3.5 V. The cell wasdischarged through an adjustable resistor which was set to 3.1 kΩ sothat the initial discharging current was 1.0 mA. After about 2.5 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #35

Anode (0.2 g): Carbon

Cathode (0.02 g): CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.02CaCl₂—0.06AlCl₃

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

For the cathode, a CaCl₂ coating was deposited on the substrate usingthe technique described above in Part A of Section IV (Electrode CoatingPreparations). A total of about 0.022 g CaCl₂ was deposited on thecathode substrate. The starting solution was 20 ml of water saturatedwith CaCl₂. The baking procedure performed between immersions and thefinal baking and annealing steps are above given in Part A(i) of SectionIV (Electrode Coating Preparations).

The electrolyte was prepared by dissolving 8.0 g AlCl₃ into 120 g SOCl₂at room temperature, and after that reaction had proceeded tocompletion, 2.2 g CaCl₂ was dissolved into the mixture at 50° C.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.9 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 3.7 V. The cell wasdischarged through an adjustable resistor which was set to 3.1 kΩ sothat the initial discharging current was 1.0 mA. After about 2.7 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #36

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.6CaS—0.4CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃—0.02CaCl₂

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

The cathode was made as follows. 4.3 g CaS and 11.1 g CaCl₂ werecombined in a quartz tube which was then vacuum-sealed, heated to 850°C., and held for two hours. After this mixture had cooled to roomtemperature, it was crushed to a fine powder using a mortar and pestle.This powder mixture was made into a paste by mixing it with 5 ml waterand 0.5 g polyethylene oxide with a molecular weight of 1,000,000 (i.e.,PEO₁₀₀₀₀₀₀). About 0.025 g of this paste was evenly applied to each sideof the carbon-on-nickel substrate and then smoothed by squeezing betweena glass roller and glass plate. The cathode assemblage was dried undervacuum at 200° C. for two hours, cooled to room temperature, andtransferred to a quartz tube which was then vacuum sealed. Thisassemblage was heated from 100° C. to 800° C. at 10° C./minute and heldfor two hours. After this heat treatment was complete, a weight checkwas performed to confirm that the total weight of the 0.6CaS—0.4CaCl₂was about 0.05 g.

The electrolyte was made by dissolving 1.1 g CaCl₂ into 192 gAlCl₃—PCl₅—0.3PCl₃ at 50° C. The starting AlCl₃—PCl₅—0.3PCl₃ solvent wasprepared as described above in Part B(i) of Section II (ElectrolytePreparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 3.2 V. The cell wasdischarged through an adjustable resistor which was set to 3.1 kΩ sothat the initial discharging current was 1.0 mA. After about 3.2 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #37

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.6CaS—0.4CaCl₂

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—0.02CaCl₂—0.06AlCl₃

Size: 4×10 mm

For this cell, carbon-on-nickel substrates, Type I (wound carbon fibers)were used for both electrodes. The materials and preparation proceduresfor this substrate design are described above in Part C of Section III(Electrode Substrate Preparations).

For the anode, excess carbon electrode active material was applied bywinding a nearly ten-fold excess of carbon fibers around thecarbon-on-nickel substrate so that the total weight of carbon on thenickel net was about 0.2 g.

The cathode was made as follows. 4.3 g CaS and 11.1 g CaCl₂ werecombined in a quartz tube which was then vacuum-sealed, heated to 850°C., and held for two hours. After this mixture had cooled to roomtemperature, it was crushed to a fine powder using a mortar and pestle.This powder mixture was made into a paste by mixing it with 5 ml waterand 0.5 g polyethylene oxide with a molecular weight of 1,000,000 (i.e.,PEO₁₀₀₀₀₀₀). About 0.025 g of this paste was evenly applied to each sideof the carbon-on-nickel substrate and then smoothed by squeezing betweena glass roller and glass plate. The cathode assemblage was dried undervacuum at 200° C. for two hours, cooled to room temperature, andtransferred to a quartz tube which was then vacuum sealed. Thisassemblage was heated from 100° C. to 800° C. at 10° C./minute and heldfor two hours. After this heat treatment was complete, a weight checkwas performed to confirm that the total weight of the 0.6CaS—0.4CaCl₂was about 0.05 g.

The electrolyte was made by dissolving 8.0 g AlCl₃ into 120 g SOCl₂ atroom temperature, and after that reaction had proceeded to completion,2.2 g CaCl₂ was dissolved into the mixture at 50° C.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of4.5 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 3.3 V. The cell wasdischarged through an adjustable resistor which was set to 3.1 kΩ sothat the initial discharging current was 1.0 mA. After about 3.5 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #38

Anode (0.2 g): Carbon

Cathode (0.05 g): Carbon

Substrate: Carbon-on-nickel

Electrolyte (in excess): 2.5AlCl₃—PCl₅—0.5PCl₃

Size: 4×10 mm

For this cell, both the anode and cathode were prepared by winding about0.2 g of carbon fibers around 4×10 mm nickel nets. The materials andprocedures for preparation of these electrodes where otherwise the sameas those of the carbon-on-nickel substrate, 4×10 mm, Type I (woundcarbon fiber cluster).

The electrolyte was prepared as follows. A molten salt mixture with theabove nominal composition was made as follows. Small lots (47.4 g) wereprepared by combining 26.6 g AlCl₃ with 20.8 g PCl₅ in a covered glassbottle and heating to 170° C. using a hot plate until the mixture becamehomogeneous. This mixture was then cooled to about 40° C. and 50 g PCl₃and 6.7 g AlCl₃ were added. These ingredients were mixed, heated to 50°C., and held for two hours. After this mixture was allowed toequilibrate, it was found that a liquid consisting of two distinctphases had formed. The top liquid consisted mostly of undissolved PCl₃and was removed entirely by skimming it off the top. The liquid that hadsettled to the bottom consisted of AlCl₃ and PCl₅ present at a 2.5:1molar ratio in which PCl₃ was present at saturation, giving a molarratio of AlCl₃, PCl₅, and PCl₃ estimated at about 10:10:5 based on theamount of PCl₃ in the top liquid. This bottom liquid consisted theAlCl₃—PCl₅—0.5PCl₃ solvent.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of3.5 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 2.2 V. The cell wasdischarged through an adjustable resistor which was set to 2.0 kΩ sothat the initial discharging current was 1.0 mA. After about 3.5 hours,the cell output voltage had dropped to 0.1 V.

EXAMPLE #39

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.25Al₂S₃—0.75C

Substrate: Carbon-on-nickel

Electrolyte (in excess): AlCl₃—PCl₅—0.3PCl₃

Size: 4×10 mm

For this cell, the anode were prepared by winding about 0.2 g of carbonfibers around 4×10 mm nickel net. The materials and procedures forpreparation of this electrode were otherwise the same as those of thecarbon-on-nickel substrate, 4×10 mm, Type I (wound carbon fibercluster).

The cathode was prepared as follows. A mixture of Al₂S₃ and carbon withthe above nominal composition was made by first combining 6.0 g Al₂S₃powder and 0.8 g polypropylene oxide with a molecular weight of 400(i.e., PPO₄₀₀). This mixture, which had the consistency of a paste, wasput into a quartz test tube, heated in air at a rate of 5° C./minutefrom 100° C. to 400° C., held for two hours, cooled to room temperature,vacuum-sealed, heated to 950° C., held for five hours, and cooled backto room temperature. This hard solid mixture of Al₂S₃ and carbon wasground to a fine powder with a mortar and pestle and mixed with 0.1PPO₄₀₀ to form a paste. Each side of 4×10 mm nickel net was coated with0.025 g Al₂S₃-carbon paste which was smoothed by squeezing between aglass roller and glass plate. This cathode assemblage was placed in alarge glass test tube with the open end stuffed with glass paste paper,heated in argon at 5° C./minute from 100° C. to 250° C., and held forfour hours in argon. This assemblage was heated thereafter in argon at5° C./minute to 500° C. and held for four hours.

The electrolyte, i.e., AlCl₃—PCl₅—0.3PCl₃, was prepared as describedabove in Part B(i) of Section II (Electrolyte Preparations).

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of3.5 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 2.3 V. The cell wasdischarged through an adjustable resistor which was set to 2.2 kΩ sothat the initial discharging current was 1.0 mA. After about 4.2 hours,the cell output voltage had dropped to 0.1 V.

EXAMPLE #40

Anode (0.2 g): Carbon

Cathode (0.2 g): Carbon

Substrate: Carbon-on-nickel

Electrolyte (in excess): SOCl₂—1.5AlCl₃

Size: 4×10 mm

For this cell, both the anode and cathode were prepared by winding about0.2 g of carbon fibers around 4×10 mm nickel nets. The materials andprocedures for preparation of these electrodes where otherwise the sameas those of the carbon-on-nickel substrate, 4×10 mm, Type I (woundcarbon fiber cluster).

The electrolyte was a saturated solution of AlCl₃ in SOCl₂ in whichAlCl₃ and SOCl₂ are present in a 3:2 molar ratio. This electrolyte wasprepared by adding 200 g AlCl₃ to 119 g SOCl₂ at room temperature.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of3.7 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 2.3 V. The cell wasdischarged through an adjustable resistor which was set to 2.2 kΩ sothat the initial discharging current was 1.0 mA. After about 2.5 hours,the cell output voltage had dropped to 0.5 V.

EXAMPLE #41

Anode (0.2 g): Carbon

Cathode (0.05 g): 0.25Al₂S₃—0.75C

Substrate: Carbon-on-nickel

Electrolyte (in excess): SO₂Cl₂—1.5AlCl₃

Size: 4×10 mm

For this cell, the anode were prepared by winding about 0.2 g of carbonfibers around 4×10 mm nickel net. The materials and procedures forpreparation of this electrode were otherwise the same as those of thecarbon-on-nickel substrate, 4×10 mm, Type I (wound carbon fibercluster).

The cathode was prepared as follows. A mixture of Al₂S₃ and carbon withthe above nominal composition was made by first combining 6.0 g Al₂S₃powder and 0.8 g polypropylene oxide with a molecular weight of 400(i.e., PPO₄₀₀). This mixture, which had the consistency of a paste, wasput into a quartz test tube, heated in air at a rate of 5° C./minutefrom 100° C. to 400° C., held for two hours, cooled to room temperature,vacuum-sealed, heated to 950° C., held for five hours, and cooled backto room temperature. This hard solid mixture of Al₂S₃ and carbon wasground to a fine powder with a mortar and pestle and mixed with 0.1PPO₄₀₀ to form a paste. Each side of 4×10 mm nickel net was coated with0.025 g Al₂S₃-carbon paste which was smoothed by squeezing between aglass roller and glass plate. This cathode assemblage was placed in alarge glass test tube with the open end stuffed with glass paste paper,heated in argon at 5° C./minute from 100° C. to 250° C., and held forfour hours in argon. This assemblage was heated thereafter in argon at5° C./minute to 500° C. and held for four hours.

The electrolyte was a saturated solution of AlCl₃ in SOCl₂ in whichAlCl₃ and SO₂Cl₂ are present in a 3:2 molar ratio. This electrolyte wasprepared by adding 200 g AlCl₃ to 134 g SO₂Cl₂ at room temperature.

A cell was assembled from the above-described cell component materialsusing a parallel plate design, i.e., Parallel Plate, 4×10 mm. Thematerials and preparation procedures for this test cell design aredescribed in Part B of Section V (Cell Assembly).

This cell was charged in constant-voltage mode by applying a voltage of3.5 V across the cell in series with an adjustable resistor which wasinitially set to 5.0 kΩ so that the charging current was 2.0 mA. Ascharging progressed, this resistor was manually lowered step by step tokeep the charging current at about 2.0 mA until it had reached a valueof about 150Ω. The charging process was continued thereafter until thecharging current had dropped to 0.05 mA. The total charging time fromstart to finish was about 2.0 hours.

The open circuit voltage after charging was 2.3 V. The cell wasdischarged through an adjustable resistor which was set to 2.2 kΩ sothat the initial discharging current was 1.0 mA. After about 3.5 hours,the cell output voltage had dropped to 0.5 V.

What is claimed is:
 1. A rechargeable battery or cell in which theelectrode active material consists of at least one nonmetallic compoundor salt of the electropositive species on which the cell is basedwherein a) at least one solid electrode phase before charging consistsof a nonmetallic compound or salt of the electropositive species of thecell, and b) an electrolyte or electrolyte solvent consistspredominantly of one or more halogen- and/or chalcogen-bearing covalentcompounds and/or salts such that the electrolyte is a liquid or has agelatinous consistency at ambient temperature.
 2. A battery or cell asgiven in claim 1 in which the electropositive species is one ofammonium, aluminum, boron, calcium, lithium, magnesium, phosphonium,phosphorus, potassium, sodium, or strontium.
 3. A battery or cell asgiven in claim 2 in which said solid electrode phase(s) consists of oneor more halide, pseudohalide, oxide, sulfide, carbonate, perchlorate,sulfate, phosphate, nitrate, or nitrite compounds, said electrode solidphase(s), and a substrate, constituting the solid portion or structureof at least one electrode, either by themselves or as a mixture withother solid phases, said other phases including metals, nonmetals, andcompounds having a cation species that differs from that of theelectropositive species of the cell.
 4. A battery or cell as given inclaim 3 in which for at least one electrode, said other phases includeat least one of ZnO, CuO, Cu₂O, SnO, SnO₂, or a transition metalchalcogenide including CoO, FeO, MnO, V₂O₅, TiS₂, and FeS₂.
 5. A batteryor cell as given in claim 3 in which for at least one electrode, saidother phases include at least one of ZnX₂, CuX₂, SnX₂, SnX₄, or atransition metal halide including CoX₂, FeX₂, or MnX₂, wherein X is F orCl.
 6. A battery or cell as given in claim 3 in which for at least oneelectrode, said other phases include at least one of carbon, silicon,boron, phosphorus, or any compound or alloy containing at least two ofcarbon, silicon, boron, phosphorus, or nitrogen.
 7. A battery or cell asgiven in claim 3 in which for at least one electrode, said other phasesinclude at least one of Cu, Ni, Zn, or Fe.
 8. A battery or cell as givenin claim 3 in which for at least one electrode, said other phasesinclude at least one aliovalent metal halide, i.e., wherein the metalvalence or oxidation state is different from that of the electropositivespecies of the cell.
 9. A battery or cell as given in claim 3 in whichfor at least one electrode, said other phases include at least onerefractory metal oxide including Al₂O₃ ZrO₂, TiO₂, MgO, or CaO.
 10. Abattery or cell as given in claim 3 in which the electrode substrateseach consist of a metal support or lead which is either uncovered orcovered with a solid phase which consists of one or more of carbon,silicon, boron, phosphorus, or any compound or alloy containing at leasttwo of carbon, silicon, boron, phosphorus, or nitrogen.
 11. A battery orcell as given in claim 10 in which the substrate support or lead metalis aluminum, copper, nickel, iron, stainless steel, or platinum.
 12. Abattery or cell as given in claim 3 in which the electrolyte orelectrolyte solvent consists predominantly of one or more of the sulfuroxides, the binary sulfur halides, the ternary sulfur halides, theoxyhalides, the interhalogens, or the covalent metal and nonmetalhalides, MX_(n), wherein M is either Al, B, C, Ca, Cr, Mg, P, Si, Sn,Sr, Ti, or V, X is a halogen, and n represents a possible valence oroxidation state of M.
 13. A battery or cell as given in claim 12 inwhich the electrolyte or electrolyte solvent consists predominantly ofone of SOCl₂, SO₂Cl₂, PCl₃, POCl₃, or PSCl₃.
 14. A battery or cell asgiven in claim 12 in which the electrolyte or electrolyte solventconsists predominantly of a mixture of halides which is liquid atambient temperature, said mixture consisting of at least two differentcompounds with the general formula, MX_(n), wherein M is either Al, B,C, Ca, Cr, Mg, P, Si, Sn, Sr, Ti, or V, X is a halogen, and n representsa possible valence or oxidation state of M.
 15. A battery or cell asgiven in claim 14 in which the electrolyte or electrolyte solventconsists predominantly of any composition within the binary system,AlCl₃—PCl₃, or within the ternary systems, AlCl₃—PC₅—PCl₃,AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms a liquid at ambienttemperature.
 16. A rechargeable battery or cell in which the electrodeactive material consists of at least one nonmetallic compound or salt ofthe electropositive species on which the cell is based wherein a) theelectrode solid phase(s), not including the substrate metal lead,consist entirely of at least one primarily covalent solid of anonmetallic element, or a covalent compound thereof, which form a partof a substrate, and b) an electrolyte or electrolyte solvent consistspredominantly of one or more halogen- and/or chalcogen-bearing covalentcompounds and/or salts wherein at least one component is a nonmetalliccompound or salt of the electropositive species of the cell, such thatthe electrolyte is a liquid or has a gelatinous consistency at ambienttemperature.
 17. A battery or cell as given in claim 16 in which theelectropositive species is one of aluminum, boron, calcium, magnesium,phosphorus, or strontium.
 18. A battery or cell as given in claim 17 inwhich solid phase(s) consist of one or more of carbon, silicon, boron,phosphorus, or any compound or alloy containing at least two of carbon,silicon, boron, phosphorus, or nitrogen.
 19. A battery or cell as givenin claim 18 in which the substrate support or lead metal is aluminum,copper, nickel, iron, stainless steel, or platinum.
 20. A battery orcell as given in claim 18 in which the electrolyte or electrolytesolvent contains one or more halides of the cell electropositivespecies, MX_(n), wherein M is the cell electropositive species, X is ahalogen, and n represents a possible valence or oxidation state of M,said halides constituting the electrolyte or electrolyte solvent, eitherby themselves or as a mixture with other compounds, said other compoundsincluding the sulfur oxides, the binary sulfur halides, the ternarysulfur halides, the oxyhalides, the interhalogens, and other covalentmetal and nonmetal halides, M′X_(n), wherein M′ is either Al, B, C, Ca,Cr, Mg, P, Si, Sn, Sr, Ti, or V, and is different from M, X is ahalogen, and n represents a possible valence or oxidation state of M′.21. A battery or cell as given in claim 20 in which the electrolyte orelectrolyte solvent, said other compounds include at least one of SOCl₂,SO₂Cl₂, PCl₃, POCl₃, or PSCl₃.
 22. A battery or cell as given in claim20 in which the electrolyte or electrolyte solvent consistspredominantly of a mixture of halides which is liquid at ambienttemperature, said mixture consisting of at least two components, MX_(n)and M′X_(n) wherein M is the cell electropositive species, M′ is eitherAl, B, C, Ca, Cr, Mg, P, Si, Sn, Sr, Ti, or V, and is different from M,X is a halogen, an n represents a possible valence or oxidation state ofM′.
 23. A battery or cell as given in claim 22 in which the electrolyteor electrolyte solvent consists predominantly of any composition withinthe binary system, AlCl₃—PCl₅, or within the ternary systems,AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature.
 24. An electrode for use in anelectrochemical cell in which the electrode solid phases consist of oneor more halide, pseudohalide, oxide, sulfide, carbonate, perchlorate,sulfate, phosphate, nitrate, or nitrite compounds wherein the cation isone of ammonium, aluminum, boron, calcium, lithium, magnesium,phosphonium, phosphorous, potassium, sodium, or strontium, saidelectrode solid phases, and a substrate, constitute the solid portion orstructure of the electrode, either by themselves or as a mixture withother solid phases, said other phases including metals, nonmetals, andcompounds having a cation species that differs from that of the mainelectropositive species of the cell, and in which the electrode solidphases are applied as a coating to a substrate as a paste, said pasteconsisting of a homogeneous mixture of powders of the electrode solidphases and a binder or vehicle consisting of either an organic polymerdissolved in a solvent or an organic polymer that is liquid at ambienttemperature.
 25. An electrode as given in claim 24 in which the binderor vehicle consists of a polypropylene oxide polymer dissolved in anorganic solvent including acetonitrile.
 26. An electrode as given inclaim 25 in which the coated substrate is heat treated to effect achemical change within the coating, said chemical change including theconversion of the polymer to carbon.
 27. An electrode as given in claim24 in which the binder or vehicle is a polypropylene oxide polymer thatis liquid at ambient temperature.
 28. An electrode as given in claim 27in which the coated substrate is heat treated to effect a chemicalchange within the coating, said chemical change include the conversionof the polymer to carbon.
 29. An electrode as given in claim 24 in whichthe binder or vehicle consists of a polypropylene oxide polymerdissolved in water.
 30. An electrode as given in claim 29 in which thecoated substrate is heat treated to effect a chemical change within thecoating, said chemical change include the conversion of the polymer tocarbon.
 31. An electrode or substrate for use in an electrochemical cellin which carbon is the predominant solid phase and is applied to a metalsubstrate support as a paste, said paste consisting of a carbon powderand a binder or vehicle consisting of a solvent and a polymer, saidcarbon powder being produced by soaking carbon fibers in a LiCl aqueoussolution, driving the mixture, heat treating the mixture, grinding theproduct to a powder, and removing the excess LiCl.
 32. An electrode orsubstrate as given in claim 31 in which the carbon powder paste isapplied to a substrate support metal consisting or either nickel orstainless steel.
 33. An electrode or substrate as given in claim 32 inwhich the binder or vehicle consists of polytetrafluoroethylene inwater.
 34. An electrode or substrate as given in claim 32 in which thebinder or vehicle consists of polypropylene oxide in an organic solventincluding acetonitrile.
 35. An electrode or substrate for use in anelectrochemical cell in which carbon is the predominant solid phase andis applied to a substrate support metal as a slurry, said slurryconsisting of either carbon powder or carbon fibers and a binderconsisting of an organic solvent and an organic polymer, and in whichthe solvent is acetonitrile, the polymer is polypropylene oxide, and thesubstrate support metal consists of either nickel or stainless steel.36. An electrode or substrate as given in claim 35 in which the carbonpowder is produced by soaking carbon fibers in a LiCl aqueous solution,drying the mixture, heat treating it at a high temperature, grinding theproduct to a powder, and removing the excess LiCl.
 37. An electrode orsubstrate as given in claim 35 in which the carbon is in the form offibers less than 2 mm long.
 38. A gel electrolyte for use in anelectrochemical cell which consists predominately of either SOCl₂,SO₂Cl₂, PCl₃, POCl₃, or PSCl₃, and that contains between about 0.5 to 5m% of MF or MBF₄, wherein M is one of Li or Na.
 39. An electrolyte asgiven in claim 38 further including one or more compounds from the groupconsisting of LiAlCl₄ and the complexes, LiR.AlCl₃, wherein R is SCN,OCN, or CN.
 40. An electrolyte as given in claim 38 further including aLewis acid and one or more salts of lithium.
 41. An electrolyte as givenin claim 40 in which said Lewis acid is AlCl₃, and said lithium saltsinclude LiX, wherein X is a halogen, LiSCN, LiOCN, and LiCN.
 42. Anelectrolyte as given in claim 38 further including one or more ofNaAlCl₄, and the complexes, NaR.AlCl₃, wherein R is SCN, OCN, or CN. 43.An electrolyte as given in claim 38 that also contains a Lewis acid andone or more salts of sodium.
 44. An electrolyte as given in claim 43 inwhich said Lewis acid is AlCl₃, and said sodium salts include NaX,wherein X is a halogen, NaSCN, NaOCN, and NaCN.
 45. An electrolyte orelectrolyte solvent for use in an electrochemical cell that consistspredominately of any composition within the ternary system,AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature.
 46. An electrolyte or electrolyte solventas given in claim 45 that contains between about 0.5 to 5% of LiF orLiBF.
 47. An electrolyte or electrolyte solvent as given in claim 45that contains between about 0.5 to 5m % of NaF or NaBF.
 48. Anelectrolyte as given in claim 45 that contains one or more alkali metalsalts wherein the alkali metal species is the same for all salts added.49. An electrolyte as given in claim 45 that contains one or more ofLiX, wherein X is a halogen, LiSCN, LiOCN, LiCN, LiAlCl₄, and thecomplexes, LiR.AlCl₃, wherein R is SCN, OCN, or CN.
 50. An electrolyteas given in claim 48 that contains one or more of NaX, wherein X is ahalogen, NaSCN, NaOCN, NaCN, NaAlCl₄, and the complexes, NaR.AlCl₃,wherein R is SCN, OCN, or CN.
 51. An electrolyte as given in claim 45that contains one or more alkaline earth salts wherein the alkalineearth metal species is the same for all salts added.
 52. An electrolyteas given in claim 51 that contains one or more of CaX₂, wherein X is ahalogen, Ca(SCN)₂, Ca(OCN)₂, Ca(CN)₂, and the complexes, CaR.AlCl₃,wherein R is SCN, OCN, or CN.
 53. An electrolyte as given in claim 51that contains one or more of MgX₂, wherein X is a halogen, Mg(SCN)₂,Mg(OCN)₂, Mg(CN)₂, and the complexes, MgR.AlCl₃, wherein R is SCN, OCN,or CN.
 54. An electrolyte or electrolyte solvent for use in anelectrochemical cell that consists predominately of any compositionwithin the binary system AlCl₃—PCl₅, or within ternary system,AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature, and contains one or more alkaline earthsalts wherein the alkaline earth metal species is the same for all saltsadded.
 55. An electrolyte as is given in claim 54 that contains one ormore of CaX₂, wherein X is a halogen, Ca(SCN)₂, Ca(OCN)₂, Ca(CN)₂, andthe complexes, CaR.AlCl₃, wherein R is SCN, OCN, or CN.
 56. Anelectrolyte as is given in claim 54 that contains one or more of MgX₂,wherein X is a halogen, Mg(SCN)₂, Mg(OCN)₂, Mg(CN)₂, and the complexes,MgR₂.AlCl₃, wherein R is SCN, OCN, or CN.
 57. An electrolyte as is givenin claim 54 that contains one or more of CaX₂, wherein X is a halogen,Ca(SCN)₂, Ca(OCN)₂, Ca(CN)₂, and the complexes, CaR₂.AlCl₃, wherein R isSCN, OCN, or CN.
 58. An electrolyte as is given in claim 54 thatcontains one or more of MgX₂, wherein X is a halogen, Mg(SCN)₂,Mg(OCN)₂, Mg(CN)₂, and the complexes, MgR.AlCl₃, wherein R is SCN, OCN,or CN.
 59. An electrolyte or electrolyte solvent for use in anelectrochemical cell that consists predominately of any compositionwithin the binary system AlCl₃—PCl₅, or within the ternary system,AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature, that contains between about 0.5 to 5 m %of LiF or LiBF₄.
 60. An electrolyte or electrolyte solvent for use in anelectrochemical cell that consists predominately of any compositionwithin the binary system AlCl₃—PCl₅, or within ternary system,AlCl₃—PCl₃—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature, that contains between about 0.5 to 5 m %of NaF or NaBF₄.
 61. An electrolyte or electrolyte solvent for use in anelectrochemical cell that consists predominately of any compositionwithin the binary system AlCl₃—PCl₅, or within ternary system,AlCl₃—PCl₅—PCl₃, AlCl₃—PCl₅—POCl₃, and AlCl₃—PCl₅—PSCl₃, that forms aliquid at ambient temperature, and contains one or more alkali metalsalts wherein the alkali metal species is the same for all salts added.62. An electrolyte as is given in claim 61 that contains one or more ofLiX, wherein X is a halogen, LiSCN, LiOCN, LiCN, LiAlCl₄, and thecomplexes, LiR.AlCl₃, wherein R is SCN, OCN, or CN.
 63. An electrolyteas is given in claim 61 that contains one or more of NaX, wherein X is ahalogen, NaSCN, NaOCN, NaCN, NaAlCl₄, and the complexes, NaR.AlCl₃,wherein R is SCN, OCN, or CN.
 64. An electrolyte as given in claim 61that contains one or more of LiX, wherein X is a halogen, LiSCN, LiOCN,LiCN, LiAlCl₄, and the complexes, LiR.AlCl₃, wherein R is SCN, OCN, orCN.
 65. An electrolyte as given in claim 61 that contains one or more ofNaX, wherein X is a halogen, NaSCN, NaOCN, NaCN, NaAlCl₄, and thecomplexes, NaR.AlCl₃, wherein R is SCN, OCN, or CN.